I have not experienced any delay issues or control issues with the games I have tried so far. I have tested PS1, nintendo, super nes, sega genesis, and N64 emulators. It works excellent for mame4droid reloaded as well. The button mapping works great for all the emulators. I have only used it with the wire that comes with the gamesklip, not wireless, not sure if that would make a difference or not.
The only thing I have not been able to figure out is how to use the sixaxis app to map touchscreen only games to the controller. My nexus is rooted and I cant seem to figure it out. But other then that all the emulators and android games that allow for external controller work excellent so far.