Could depend one what router you have too. I've had zero issues with my iPad 2's wifi, and prefer it over my Nexus 7 basically just because of the larger screen. (Otherwise I suppose I'd prefer having more browsers available.)
I haven't had the Nexus long but the performance seems good. The 2x RAM (compared to the iPad 2 or Mini or iPod 5) is definitely noticeable. Should actually have about 1/3 to over 2x the CPU power available too.
While my iPad 2 connects flawlessly to my friend's wifi, I've noticed my iPod 5 disconnects constantly, but is fine with my Airport Extreme soooo I kind of think maybe some wifi chips are just finicky with some routers :-/