When I saw the 100% detection rate, I actually thought that you may have used av-test.org, because their tests also show 100% detection rates.
I think having some sort of evaluation of the apps is better than nothing. If you don't test them, the consumer would not know if the apps are even doing anything. I would install an app with a "100%" detection rate over something with "90%" or "95%"
But me being a application security consultant, testing mobile apps most of the days for my day job, it's a bit hard for me to accept the 100% detection rate for mobile AVs.
Here's a good example. The mobile AVs can only scan downloads only if they are downloaded though the standard downloaded app and copied to a location on the disk such as the download folder of the mobile. If an app decided to download something an copy it into a a folder that only that app has access to, then the AV is simply ineffective. There's no way for the AV to intercept the connections that the app is making.
There was a web site called jailbreakme.com. Before a certain iOS version it was possible for anyone to visit that website using the mobile safari web browser and get their iPhone jailbroken. This was possible because of a vulnerability in the browser. If a malware exploited this vulnerability, it could have got root privileges (the highest level of privileges). Unfortunately, no mobile AV can stop these types of exploits.
The only way for the AVs to even have a decent level of detection rate is if it's shipped as part of the OS. In iPhones case, apple has to develop it. In Android's case, either Google or the OEM vendor (Samsung, HTC, etc) has to ship it.
So, I'm still very skeptical about the thoroughness of Av-test.org's tests.