I enjoy the realism and power of the Playstation 4 and Xbox, but in the end it’s the gaming concept that matters most.
I always felt Nintendo had to drastically improve on render quality, and they have done a decent job. Content promise looks good as well.
The Wii was a revolution in gaming, the Wii U a bit of a gimmick, so it is well timed of Nintendo to come with an original concept.
I like the controllers and how they balance using buttons and gesture-style interfacing though they will have to last long on a charge.
Even better would be if it integrated a phone. I would, for one, find a way to make it wearable.
They could have done better on the industrial design and be inspired for example by fashion to design portable products. This does not remind me of Nintendo nor make for a very good tablet design but I like that it looks a bit more mature.
I think it will have reasonable success just because of the gaming concept.