I've been moderately happy with my Wii U since picking it up... I just really wish there was more to do on it.
I knew going in that it was poised to stumble out of the gates with a launch lineup mostly consisting of games I'd already played to death on other consoles, and a lot of ho-hum titles... but I had played Mario and Rayman at the Wii U Experience event in Chicago, and loved them both, so I took the plunge. If I'd have known what was going to happen to poor Rayman, though...
That said, my time with New Super Mario Bros U was just magical - the game doesn't do anything "new" in terms of the Mario formula, but it didn't need to. Just being a modernized take on Super Mario World was enough for me... the game made me happy and made me feel like I was 12 again, and really made the whole purchase worth it for me. As someone that's grown tired of a lot of what the industry's been pumping out, that nostalgic feel with the visual polish of that game was just what I needed to be interested in gaming again.
NintendoLand is a lot of fun, but as a guy that plays mostly singleplayer locally (for some reason all my friends live an hour away, so meetups are bi-weekly at best), it doesn't have a ton of meat on its bones. When it's fun though.... oh is it ever fun!
ZombiU is a bit clunky, but I find it a lot of fun... it looks decent enough and has a lot of great ideas. There's enough there for me to recommend people play it, but sometimes the controls and the "feel" of the game frustrate me. A little more polish on that one and it could've moved some systems.
Other than those three games though... Nothing's really grabbed me. Until the update hit it'd literally been months since I turned it on. I'm chomping at the bit for something new to play, and no one's delivering anything anytime soon. That disappoints me.
I need to make a couple of eShop purchases, like the Nano Assault game which I hear is really fun, and now that the 3DS version of Monster Hunter has me bitten with the Monster Hunting bug again, I need to get that game too (I was going to pass since I invested hundreds of hours in the Wii one only to be left with no way to import my character or even move my save off of the old Wii).
Would I recommend a Wii U to someone that doesn't have one yet? Back in December I would have, but right now I don't think I would unless they really like Mario. The latter half of this year needs to produce some gems for sure. The technology is actually really cool and I love the gamepad a lot more than I expected to. I just, you know, need some games to play!