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The Vizio M-Series Quantum 65-inch (M658-G1) ($748) is a fascinating offering from a manufacturer best-known for its thrifty smart TVs. This year, Vizio's play is to add quantum-dot enhancement to its full range of TVs, from the premium flagship models to economy-class sets. In the M-Series, Vizio's midrange line, the result is a surprisingly premium experience on a sub-$1000 TV.
The enhanced display delivers fantastic color and brightness, while Vizio's SmartCast operating system offers plenty of flexibility with its combination of free content, included apps and built-in Google Chromecast for enjoying thousands of additional apps and services. Overall, the M-Series Quantum is so impressive that it makes our list of best TVs you can buy.
Editor's Note: (8/26/2020) The Vizio M-Series Quantum is still being sold, but it's on clearance from most retailers. We've updated the pricing and availability to reflect these changes. The original rating and recommendation remains unchanged.
If you bought the Vizio M658-G1 last year, you're probably due to refresh the software. Check our guide to learn how to update your Vizio TV to the latest version of SmartCast.
Vizio M-Series Quantum (M658-G1) price and availability
While we looked at the 65-inch model of the M-Series Quantum line, the quantum-dot- enhanced smart TV is available in other sizes, ranging from 43 inches up to 65 inches.
This range of sizes – every one equipped with quantum-dot enhancement, HDR support and full array local dimming – means there's a model that should fit your home, whether you're crowded in a tiny apartment or have room for a larger set. Though we've only tested the 65-inch model so far, the similarity in feature sets and designs means that most of our conclusions from this review will apply equally to other sizes in the model line.
However, two of the models that were originally sold as part of the M-Series Quantum line, the Walmart-exclusive models 55-inch (M557-G0) and the 65-inch (M657-G0), are similar, but slightly lower-priced models. (The appear now to be out of stock.) These models offer far fewer backlighting zones than the more expensive versions sold through Best Buy. The cheaper 65-inch model has 20 dimming zones instead of the 90 seen in our review unit. The 55-inch (M557-G0) has only 16.
Vizio M-Series Quantum (M658-G1) design
The overall design of the Vizio M-Series Quantum is largely unchanged from the previous year, but this is definitely an instance where there's nothing that particularly needed changing. Slim black bezels surround the top and sides of the display, with a thicker bezel running along the bottom edge. In the bottom right corner of this is a silver Vizio logo, the only significant feature on the front of the set.
The TV measures 57.3 x 35.6 x 2.8 inches without the stand. The back of the TV isn't quite as bland as you'll see on most TVs, thanks to a patterned texture that covers the rear of the cabinet. Made of black plastic, the TV's construction is reasonably sturdy, and weighs 53.4 pounds.
Included with the TV is an attachable stand consisting of two boomerang-shaped metal feet that attach fairly quickly with a Phillips head screwdriver. The stand does have a deeper footprint than the 2.8-inch thickness of the TV, so it requires a tabletop that can accommodate 11.8 inches of depth. If you would rather hang the Vizio on the wall, it can be attached with a 400 x 200 millimeter VESA mount.
Vizio M-Series Quantum (M658-G1) ports
On the back of the TV is a collection of ports, divided into a row of right-facing connections and downward facing ports. I'm not generally a fan of this input configuration, since it virtually guarantees that some of the ports will be hard to reach regardless of how the TV is set up. This is an admittedly small quibble, since most users will set up their TV once, and only occasionally change what devices are connected to the set.
Regardless, the M658-G1 is outfitted with four HDMI ports (two on the side and two on the bottom) with one offering audio-return channel (ARC) support for simple connection of soundbars. There's a single USB port for connecting a flash drive or powering a dongle and an optical connection for older digital surround-sound systems. RCA stereo jacks are also available for plugging in speakers. And finally, there is a connection for HD antennas – a feature only reintroduced on last year's Vizio TVs.
For network connectivity, the TV has an Ethernet LAN port and built in 802.11ac Wi-Fi. It does not, however, have Bluetooth, so you won't be able to connect wireless headphones to the TV without some sort of plug-in adapter.
Vizio M-Series Quantum (M658-G1) performance
With a combination of quantum dots to boost brightness and color and full array local dimming for deeper blacks and brighter brights, the M-Series Quantum delivers some really outstanding performance for a set that sells for less than $1,000.
Watching a movie filled with bright colors and fast action, like Spider-Man: Homecoming, I was pleased to see that colors on the M658-G1 looked true to life. A daytime shot of the Washington Monument was filled with red, white and blue flags, lush green landscaping and plenty of moving people, and it all looked appropriately smooth and vivid.
With support for both HDR10 and Dolby Vision, high dynamic range (HDR) content looks great on the M658-G1, as well. A nighttime fight scene of Spider-Man duking it out with a villain on a dark beach was sufficiently dark, but punctuated with bright flames and glowing lights. And unlike the performance we saw on last year's P-Series Quantum PQ65-F1 (Vizio's first quantum-dot display), the individual backlighting zones didn't cause the sort of distinct flaring that was so prevalent on that set.
Fast action was also very smooth, with none of the choppiness you might run into on some affordable sets. The 60Hz display ably kept up with fast-paced action, whether it was Spider-Man swinging through the city or a Replicant fistfight in Blade Runner 2049.
The M-Series Quantum turned in excellent color quality in our lab testing, as well. When measured with our X-Rite colorimeter and CalMAN professional calibration software, the Vizio's panel reproduced 99.92 percent of the Rec 709 color space. That's in line with the TCL 6-Series Roku TV (99.96 percent) and the Samsung Q6F QLED TV (99.93 percent), the M-Series Quantum's closest competitors.
Color accuracy, on the other hand, was slightly off, with a Delta-E rating of 3.6 (closer to zero is better). That's slightly less accurate than either the Samsung Q6F QLED (1.49) or the TCL 6-Series (1.1), and last year's P-Series Quantum was better (slightly) at 2.8. In actual viewing, the color errors were hard to see, but whites tended to skew blue, and greens were slightly oversaturated.
MORE: Best 55-inch TVs
Finally, the M658-G1 managed to be quite bright, driving 647 nits of peak brightness. That's even better than the TCL 6-Series (607 nits) and more than double the 300 nits that are commonly seen in this price range.
We also connected the Vizio to our Xbox One X to check out the gaming capabilities. The TV supports 4K gaming at 60Hz (as well as 24 and 50 Hz), and 10-bit color. HDR support is available for both games (HDR10 only) and app content (HDR10 and Dolby Vision). But with a lag time of 29.9 milliseconds, it's not the most responsive display out there. It will do fine for the casual gamer, but for competitive players who want a TV that can keep up with twitchy fast-action games, we usually recommend sets that test at 20 milliseconds or less.
Vizio M-Series Quantum (M658-G1) audio
Vizio outfitted the M658-G1 with a pair of 20-watt speakers designed to match sound quality to the enhanced display. And overall, things sounded great – and impressively loud.
Listening to Ramin Djiwadi's "Light of the Seven" from the "Game of Thrones" soundtrack, the dichotomy of deep cello and emotive piano and violin was reproduced very well. However, the bass-heavy cello did suffer from some distortion as the volume crept up above 60%, and the faintest hint of cabinet buzz could be heard at 90% volume.
Aside from this, however, the speakers produce excellent volume and impressive bass for not having a dedicated subwoofer. There was also some clipping at high volumes, and what should have been bright notes were slightly muted.
Vizio M-Series Quantum (M658-G1) smart features
With this latest round of TVs, Vizio has rolled out SmartCast 3.0, the latest version of its smart-TV platform. The update has a richer interface than previous versions, with an added row of recommended content and a richer selection of locally installed apps.
The new lineup has expanded to 30 apps, including Netflix, Amazon Video, Hulu and Vudu. Thanks to a partnership with PlutoTV, Vizio also offers a dedicated streaming channel called WatchFree, which gives you a linear TV watching experience with over 100 free channels, including sports, news, cartoons and movies.
YouTube is generally included in the app lineup, but at the time of our testing, a temporary issue meant it wasn't available. Vizio says they're working with YouTube to fix any issues, but in the meantime, users can still enjoy all of the YouTube apps using their phone and the TV's built-in Google Chromecast. (Editor's Note: Vizio tells us this issue has been fixed, and YouTube is again available. You may need to update your SmartCast software.)
That Chromecast functionality is an added treat for anyone that has a phone full of streaming apps, since it allows you to cast the app right to the TV without any loss of performance. And added in this year's TVs is support for Apple AirPlay2, letting you share just as easily from your iPhone or iPad.
Vizio M-Series Quantum (M658-G1) remote control
Vizio TV remotes have a distinctive look and feel, and you'll either love it or hate it. The slim design is rectangular, but with an oval profile that makes it very comfortable to hold. A large square directional pad sits in a prominent position, above the numbered buttons and channel and volume controls. I don't particularly love the plastic surface or the mostly featureless directional pad, but it's a serviceable design.
I much prefer the accompanying Vizio app, which includes a remote control function. All of your remote buttons are replicated on the touch screen, and give you full control of the TV set. The app also includes streaming and casting options that make it easy to either share stuff to the TV or enjoy the same content on your phone.
Vizio M-Series Quantum (M658-G1) verdict
Vizio has made major strides in the last couple of years, and this year's quantum-dot push has kept up that momentum by offering an excellent display at a great value. For a set that is arguably the middle child in Vizio's lineup, the M-Series Quantum delivers great brightness and HDR performance, solid color and picture quality, and better-than-average sound. With an evolving smart-TV platform and plenty of ports and features, the Vizio M-Series Quantum 65-inch (M658-G1) gives you a lot to love for its under-$800 price.
The M-Series Quantum is good enough that it unseats our previous favorite in this price range, the TCL 6-Series Roku TV. While the TCL's Roku platform and overall performance are both excellent, the Vizio M-Series Quantum 65-inch (M658-G1) edges it out with the vibrant quantum-dot display and ever-improving smart-TV functionality.
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Brian Westover is currently Lead Analyst, PCs and Hardware at PCMag. Until recently, however, he was Senior Editor at Tom's Guide, where he led the site's TV coverage for several years, reviewing scores of sets and writing about everything from 8K to HDR to HDMI 2.1. He also put his computing knowledge to good use by reviewing many PCs and Mac devices, and also led our router and home networking coverage. Prior to joining Tom's Guide, he wrote for TopTenReviews and PCMag.