Since the Wii U boasts newer hardware, it is obviously more powerful than the other consoles at the moment. That said, how does it compare to a modern gaming PC, though?
Not really... Actually, I'd say Nintendo is finally on the same level as current gen consoles. They are finally HD Capable, and AMD provided the GPU inside which finally has DirectX11 support. It's more on the level of the old PCs with the Core 2 CPUs in em, though CPU shouldn't be handling your Graphics unless it's an APU.
I'd say it's finally up to par with my 2005 rig that had a Core 2 Quad Extreme in it, after one of the GTX8800s crapped out and I had to take it out of SLI.
Bottom Line: Wii U, like the Wii, will have one or 2 titles that can interest a serious gamer, but is mostly geared towards casual gamers and children. Especially with the next Xbox (Code named "Infinity" atm) rumored to be unveiled at E3 2013 and released by Christmas Season 2013, imho not worth buying. And I think MS will keep the timeline because their big thing with Win 8 is the whole "Same screen" thing they're pushing, and they already have 3 of 4 out in the market, they won't stall completing it.