It's a slow burner. The first year has been very slow, as it was for the 3DS, but now there are a load of exclusives coming that will result in a surge in sales, and hopefully more 3rd party support.
I feel like it is aiming at a different audience to the Xbone and PS4, and that is why so many gamers slate it. It isn't attracting hardcore gamers, but still has a massive casual fanbase, that will continue to grow. It's real advantage is with a low price hardcore gamers may still purchase one as a 'second console' for the 1st party exclusives like smash bros, thus getting the best of both worlds. That worked great for the Wii, which lets not forget sold the most of the consoles in the last generation.
I don't have one, but it certainly isn't out of the question when some great games do start to come out. I'm a sucker for smash bros, and a good new Zelda title would be hard to resist. For now I'm content with my PC.