I've gotta say that I absolutely LOVE my Wii U, but I've always enjoyed Nintendo over the others anyway. I'm also kind of a poster child for the Wii U's key features. When my wife or kids want to use the TV, the off-TV play option is the best.
Games we have on disc:
Monster Hunter 3 Ultimate (which I alone have almost 300 hours into and transfer to my 3DS to play with my wife. She always gets the TV for our multiplayer. ALWAYS. Its also the main reason we got the system.)
New Super Mario Bros. U (with New Super Luigi U DLC)
LEGO City: Undercover
Pikmin 3
Super Mario 3D World
Donkey Kong Country Tropical Freeze
Sonic Lost World
Downloaded games:
Nintendo Land (BEST PARTY GAME EVER)
The Legend of Zelda: The Wind Waker (A MUST PLAY ON WII U)
Mighty Switch Force (1 and 2)
Toki Tori (1 and 2)
Tank! Tank! Tank! (Free version with single player campaign DLC)
Mutant Mudds
Wii Fit U
Art Academy
Wii Sports Club (nothing unlocked, but I enjoyed the free days. Considering getting Bowling and Golf.)
NES Remix
Dr. Luigi
I've also got a bunch of Virtual Console games. The off-TV play and save states are great features. (Save states are the only reason I got through Super Ghouls n' Ghosts.)
Games aside, we also use it as our primary Netflix, YouTube, and Hulu system. Because of that we don't have regular cable. (We don't use Nintendo TVii due to this, but oh well.)
All in all, the Wii U has been the most fun I've had in a long time, and really tailors to my gamer family's play styles and preferences. I can't wait for Mario Kart 8 and Smash Bros.
If you have a lot of people wanting to use the TV when you play games, the off-TV feature sells itself. If you enjoy Nintendo's history of solid platforming games (Mario, DK, etc.), I'd say go for it. Its been a blast.