So I'm one of a relatively small number of Wii U owners, and I'll be honest, I've been a little disappointed. I think it's a good console and the games I have for it are good, but there has been so little that I eventually got a PS4 to supplement it (though to be perfectly honest, I haven't been playing a ton of PS4 games either, which might be due to a recent World of Warcraft expansion.)
For that reason I'm a little mixed on my reactions to the announcement of a new Nintendo console, though I realize that, as it releases next year, it will have been about four years since the Wii U, which isn't that unreasonable for a new console.
The Switch's most important feature is that it is a hybrid mobile/console. At home, the Switch will sit in a little stand by your TV and you'll have a conventional controller to play games on the TV. However, you can pull the Switch out of its stand and attach controller-like extensions with joysticks, d-pads, and buttons and then use the console as a mobile device.
Likewise, it appears you'll be able to set up the console on a desk and use a separate controller if that's more comfortable.
In terms of console power, I'd expect this to, as usual, be a step or two behind the other major players. One of the games in the announcement video they showed was Skyrim, which at this point is five years old and two generations behind (still an awesome game.) Still, we've gotten to a point where the difference in graphics is kind of hard to tell from one generation to the next, so I'm not actually that concerned about that anymore. (Also, I'm getting older, so the Xbox 360 still feels pretty current to me even though it's been officially obsolete for a few years now. Jeez, has it really been eleven years since that came out?)
Personally, I'm going to be a little more hesitant this time to pick up the new console (though let's be honest, at some point I'll probably get it) given how disappointing the Wii U library has been. I know that Nintendo is starting to work with other companies a little more (they've got an app coming out for iOS) and perhaps if they can start playing nicer with third parties we might see them reclaiming some of their old territory, but I think that for now, as it has been for a while, Nintendo machines are best for getting Nintendo games, and that means a smaller library.
Still, I'll be following the console closely.