Comparing an iDevice and aDevice is fairly pointless, it all depends on what are you going to do with it. I'd recommed n7 as it is better price/performance value (at least in finland, where apple devices are ridiculously priced...)

But generally:
If you intend to use it just for media consumption -> get an iPad.
If you intend to tweak/tune/mangle/misuse it -> get nexus.