Third-party security apps shouldn't be deleted just yet.
The updated malware scanner that Google launched alongside Android 4.2 Jelly Bean detects only a small number of threats, a researcher has found. North Carolina State University computer science professor Xuxian Jiang said the Android scanner is "still nascent" due to a low detection rate of 15.32 percent.
"Overall, among these 1,260 samples, 193 of them can be detected," Jiang noted within his research report. "There exists room for improvement. Because of the introduction of this service, people may start to wonder, 'Are third-party security apps still necessary with Android 4.2?'"
Jiang added that while the new verification service doesn't boast a strong detection rate, it delivers side-loaded apps, such as the Amazon Appstore, for the first time in the mobile operating system's history. He went on to commend Google for at least including a malware scanner for Android's Google Play store, calling it "an exciting security feature". Jiang complimented the search engine giant for taking "measures to better protect Android users."
Jiang carried out a second batch of tests that includes a comparison of 10 third-party anti-virus engines, including ones from Avast, AVG, TrendMicro and Symantec.
"Overall, the detection rates of these representative anti-virus engines range from 51.02 percent to 100 percent while the detection rate of [Google's] new service is 20.41 percent."
"By introducing this new app verification service in Android 4.2, Google has shown its commitment to continuously improve security on Android," he added. Jiang also referred to Google's recent acquisition of VirusTotal as a promising sign for the future.
"We noticed that VirusTotal (owned by Google) has not been integrated yet into this app verification service. From our measurement results, VirusTotal performs much better than this standalone service. We expect such integration in the future will be helpful."
During the third quarter of 2012, Android’s malware issues led to the discovery of "a whopping 51,447 unique samples", according to security firm F-Secure.

no kidding that is what i was wondering
I have been using Android devices for almost 3 years without detection software and haven't had a single infection.
Surf trusted sites, read user reviews before installing apps, and be aware of dodgy links off search engine results.
During the test, each engine was given a number instead of a name (AV1 - AV10) so that information is unknown at this point. AV1 and AV3 both achieved 100%.
...one can have a vast array of choices to be made by informed consumers (from the favorite AV app to whether allowing sideloading or not).
There, I finished the sentence for you. You're welcome.
..one can have a vast array of choices, just cross your fingers it's not malware.
Edited properly...lol
This is the guy creating malware for Android, thats how he makes his $7k per month.
Well, after digging through the source linked here, and going to another link there, I found this... "Packages that detected more than 90 per cent of the Android malware thrown at them included Droid security software from Avast, Dr Web, F-Secure, Ikarus, Kaspersky, Zoner and Lookout."
I use Lookout! So I'm happy.. best of all (and shockingly), its Free!
"Products that picked up more than 65 but less than 90 per cent of Android malware included applications from established desktop players (AVG, Bitdefender, ESET, Norton/Symantec, QuickHeal, Trend Micro, Vipre/GFI and Webroot) and a couple of mobile specialists (AegisLab and Super Security)." I hope ESET is in the high 80's at least..
"Android security products from Bullguard, Comodo, G Data, McAfee, NetQin and Total Defense fell into the third range (detection of between 40 to 65 per cent)." Not surprised about McAfee..
"It should be noted that Bitdefender, ESET, Trend Micro and Vipre missed the top category by just a few samples. The average family detection rate for these four products was in the area of 88.1% to 89.9%."
http://www.av-test.org/fileadmin/pdf/avtest_2012-02_android_anti-malware_report_english.pdf
A new report will be out in Feb