Prayaya V3 fully tested.
Basically, it allows you to launch most apps and games off a USB drive BUT not officially claimed any app and game.
A few apps that I have tried on it: Firefox, Opera, Safari, MS office, Nero, Winrar, Virtual DJ, Skype, Plants vs Zombie, KM Player, Yahoo Messenger, MSN, Picasa. These are my daily used apps. And they work perfectly.
However, there are some that seems not working on it like Google Chrome, PhotoShop, Coreldraw.
Also I found that Prayaya V3 seems to write registry into USB but not a host computer. I think that is why it can launch most apps. a good advantage is that not any trace will be left on a computer if you run it off a USB drive.
Generally, I think it is a cool ware that is worthy of a try. I like its cool interface, cool feeling switching between two systems though actually not. However, if you just want to run common apps off a USB drive, I think PortableApps.com is enough for you. If you want to go furthur, Prayaya V3 is a good try.
If you like, I would like to release more information about using it.