Really only have experience with Rayman Legends, and a bit of a someone else's ZombiU. I played Monster Hunter on the Wii. Rayman is a great game for sure for the price, personally the most fun, so I'm going to go along with that. A favorite out of those few.

Look like I need to try W101 and Lego City Undercover. Maybe AC4 as well, I've never owned anything in the series, I played some of Revelations with a friend and it was just okay.

Knytt Underground.

Despite not being an exclusive.

I love the tough-as-nails challenges, the abundance of secrets, the spacey music, and the many amusing quips from Cilia and Dora.

1. Wonderful 101, epic boss fights, fun and unique gameplay, surprisingly interesting story, likeable characters, good challenge
2. Dues ex human revolution, haven't played a lot of it yet but overall good story so far, you can choose how you tackle parts of the game, good voice acting, nice challenge.
3. Zombi u, interesting concept, Steep difficulty, good use of gamepad, actually quite scary at times.
4. Rayman legends, beautiful art style, some unique levels, uses the gamepad although those levels get a bit dull after a while, but overall pretty disappointing.
I highly recommend the top three. I haven't play Lego city yet I'll have to give it a look soon.

Even though Darksiders II launched on other systems before, I'll still take it on this one. One point going for it is the price. (got mine for 19 bucks) There is a huge world to explore, awesome music and also fairly good integration of the Wii U gamepad (Map or inventory)

Overall a real surprise to be honest, I wasn't expecting such a good game.

*notable contenders: Batman Arkham City;

W101

Rayman Legends a nice runner up.

BLOPS2

I answered TW101.

But EDGE ($2 on the eShop!!!) and Need for Speed also both get a lot of playtime too.

Definitely want to give both a shot.

Probably batman arkham city. Wii u version is the definitive version of that game. Darksiders 2 is also really good.

ATM ZombiU.

True survival horror, pretty scary at times, makes decent use of the gamepad.

I would have to say Rayman Legends. It was good enough. A little bit too much like Origins but it was pretty good.