Why is my AirPlay so unreliable?

I have both a 2nd and 3rd gen ATV. Both wireless with an Apple Airport Extreme (N). AirPlaying a video from my iPhone 4s takes forever. Mirroring from my 3rd gen iPad is awful. It is choppy and often just doesn't work. Very frustrating....

FYI if I use home sharing and play via my computers iTunes library it works perfectly. Netflix streams great. But anything dealing with AirPlay sucks.