I think the wii u can also have component out for audio as well as hdmi for video. that's how I have mine setup. my wii u is outputting through my surround sound speakers at this very moment. my receiver is very old, so it has no hdmi. the only other option I know of is an hdmi to hdmi+optical (my receiver has several of these). that's what I had plugged in, but I have it unplugged at the moment after breaking something on my entertainment center. I'll replug it back in, because I was able to get surround sound with the switch with it, and it still outputs to the tv as well even though it's being split.
--------------------- MERGED ---------------------------
I personally prefer the wii u myself. I play mine daily, though the wii is still plugged in. I've hacked the hell out of it with cbhc, regionhax, rednand, neek, virtual wii in general, virtual wii theme.