Been using it for a day. Android TV will be huge. Apps are actually usable. If you're into casual gaming, you can get controllers for it and there are some decent games. And of course it also acts like a Chromecast if you just want to cast something from your phone/computer.

On a side note, it only took me a day to get my Android game working on the thing (using the controller with joysticks instead of a touchscreen). There shouldn't be a huge barrier to entry for apps that are already made for phones/tablets.