The RDR-HX910 is the only 250 GB unit in our selection. We weren't able to test the HX710, which has a 160 GB disk; other than the smaller drive (and price tag) it is the same, so all the same observations apply.
(Note that the Sony has not yet been released in the US, but it will be available soon.)
Sony was the first to offer a recorder compatible with both the DVD+R/RW and DVD-R/RW formats. With this new line the manufacturer has scored another point, by being the first to offer a double-layer model as well. The RDR-HX910 is the first home DVD writer that accepts double-layer DVDs (DVD+R DL). With their 8.5 GB of storage capacity, you'll be able to record up to 4 hours in DVD mode and 13 hours at maximum compression. Remember that the media are writable only once, however. For now the rewritable versions can hold only up to 4.5 GB, or 2 and 6 hours respectively.
The total storage capacity with the 250 GB disk is a whopping 428 hours with maximum compression, and a little better than 100 hours in DVD quality.
All the newer models of digital recorders from Sony have the new Intelligent Scene Chaptering system. With this feature, the unit automatically chapters all recordings using a scene-change algorithm, somewhat similar to what's available with video editing software. When you select a recording, the various sequences are displayed in the form of successive thumbnails, so commercials are clearly identified, making it easy to identify them. Similarly, when you transfer one or more programs to a DVD, the menu will show the breakdown into chapters. This makes the DVDs you burn very easy to use. This system will also be operative when you digitize video from a camcorder, making editing your films easier.
In the area of ergonomics, Sony already has a lot of experience under its belt, and has several proven solutions. For the RDR-HX910, they've struck the right compromise between a wealth of functions and easy access to them. The automatic scene detection feature contributes greatly to simplification. Navigation in the menus is intuitive; with exemplary design. The remote control is also easy to handle. On the other hand, while it's common to find the less frequently used functions behind a cover; for example, Sony has hidden the recording button there.
As for connectivity, nothing has been left out. There are composite and S-Video inputs and outputs, a Peritel/SCART connector, and also a YUV output. For sound, there are optical and coaxial digital audio outputs. Finally, there's an iLink (DV) connector and analog audio and video inputs on the front panel.