I'm playing Deus ex: HR DR with it and it works great with the game. you got like instant access to your stash and stats on the gamepad.
It's so smooth that the regular main menu, which is still on the TV, feels awkward.

The only minor thing is the battery life. But it does force me to take a brake now and then, so it's not that bad :).

Yeah, the thing lasts a few hours before needing to be charged, which sucks.  Luckily, my outlet is arm's length from my sofa so I just plug and keep playing!  Plus I bought a cable from amazon.com to use the charging cradle via usb on my TV.

This is more for the OP's information than for you, Stefan.

In comfort its the worst but makes up for its losses in capabilities.

Personally, I didn't find it comfortable when I initially started playing my Wii U but it started to grow on me after a day or two. Even then, I still prefer other controllers over the Wii U gamepad.

The lack of analogue triggers is a real killer for some games. I much prefer playing Need for speed most wanted on ps3 than my wii u because of lack of analogue triggers. A very cheap move by Nintendo. They put a NFC chip in the gamepad but skimped on essential features. I've also witnessed a small child in a store struggling with the size of the gamepad which surely if anything the wii u is aimed at a younger audience. I honestly believe a revised wii u will come out with a smaller gamepad and screen, in fact the console itself is fine its just the gamepad that needs updating. The touchpad screen is fantastic though, a brilliant feature. The size of it was the mistake. If they had put a smaller screen in, they could have afforded analogue triggers and it would have increased battery life.

The xbox one not only has analogue triggers but they have added individual rumble to them so when using different guns for example it can have different kickback. Great feature.

General quality of the gamepad is good and the screen quality is great. Battery life is slightly annoying to the point I now just leave the charging cable in so its not really a wireless controller.

incredbly confortable.
but it is a little more heavy than others.
But i love the right analog stick above the bottons!

Although only needed in racing/driving games, the lack of analogue triggers is a stupid decision by Nintendo especially since the Gamecube had them.

Apart from that it's an excellent controller.

Well, I got a hands on with the PS4 and Xbox One, today. I gotta say the two new gen controllers feel of a much higher quality than the two Wii U controllers--and both feel greatly improved over their 7th gen counterparts.

Wii U controller doesn't feel bad...in fact, it's quite good. The two newest HD consoles definitely have it beat, though. They just feel more solid.