These are things I am glad about, some of which I realized beforehand and some I didn't.
1) The WiiU Game Pad is a pretty good controller even without the screen on it, when it's a game where a traditional controller is a good fit. The analog sticks are very responsive, the button layout and the physical contours of the controller are comfortable in the hand, and the screen is just a nice bonus.
2) NintendoLand is a good, solid, way to get used to using the Game Pad. It's a little cutesy, but the various activities are all modeled after beloved Nintendo first party franchises. The Pikmin game in NintendoLand is a household favorite.
3) Nintendo's attempt to increase their attach rate by offering a free download game with the purchase of Mario Kart 8 may be working a little bit. (It's still going to go on through the end of July, so if you were thinking about getting a WiiU this summer, it's not a bad way to start.) We opted for New Super Mario Bros. WiiU, since we already picked up Pikmin 3 and our console was bundled with Wind Waker HD.
4) My older son seems to be a little better at Mario Kart 8 than I am, and I'm actually really excited about that. (For those of you that are wondering, the answer is Rosalina, the Circuit Special, the Slicks, and the Cloud Glider. We don't have the Cyber Slicks unlocked yet.) We've even managed to win some races playing on the internet.
5) My younger son spends most of his time on the WiiU playing regular Wii games. At the moment, everyone is taking another swing at The Legend of Zelda:Skyward Sword when we're not playing Mario Kart 8 or New Super Mario Bros. WiiU or Pikmin 3.
6) If you're bad at a particular level of New Super Mario Bros. and you're playing the Wii or WiiU versions, eventually an exclamation block will appear at the beginning of the level. Ordinarily this would not be a big deal, since it's there to ask you if you need help. If you hit the block, Luigi shows you a way to get through the level. It's just that the noise that the game makes when that block is present sounds an awful lot like a doorbell, which means that our dogs have to bark at it.