Its doing pretty decent. I agree that Google should have built a better box than that cheap Nexus Player. Hopefully they will announce something nicer soon.
Right now its in Sony, RCA, Phillips and Sharp TVs. If google can convince someone like LG or Vizio to jump in it will be game over. The ecosystem is already growing really well and has most services, just not growing Apple TV fast.
Also live channels is sick and will be really neat if more players take advantage. The features in N Preview are also looking great for TV.