Looking at the SPECS on the thing, I'd say the only thing the tablet has going for it is portability and resolution (camera resolution ... or just not including the HDTV resolution part of the Wii U)
The WiiU is going to have a lot of really stellar games coming within the next year (at least, announced as such), and is pretty fun to play around with. Off-screen play with the tablet has actually completely changed the way I play my games, so I think for that alone it's worth a look.
The Tab might be a better choice if you are a tinkerer/hacker by nature. You will get many more hours of enjoyment out of making that thing jump through hoops than you would with the WiiU. However, you're really counting on community support for hacking it, so look into that first.
I've also found that once I was done messing with getting my Android tablet(s) running just so, I never really used them again. I don't think they ever really came up with a "killer app" for tablets that you couldn't do better with something else. Opinions vary, though.