I recently bought FPSe and tried it with my PS3 controller. The controller works very well with it since the Playstation has kept all their controllers the same design (as opposed to using the PS3 controller with the N64 emulator). I've only tried 2 games so far, Final Fantasy 6 and 7, and FF7 lags a LOT and eventually freezes. I imagine it will work well with less graphic intensive games.
if you have a good router no lag at all. there are many videos on youtube you can see.
only wifi because the bluetooth is slow and cover small distances. if you not have a router, you can establish a connection point to point between the two devices with the function Tethering / portable hotspot of your device.
with the same app DroidMote Client (free) you can control also windows and linux for free. is the only one with real multitouch simulation.