This looks like a stylish little box and I like the idea of it being a full-fledged living room computer with Linux on it. So long as it handles streaming services like Netflix and Amazon Prime as well as games, it could be a hit.
I'm not sure if they're appealing to a broad enough market, though. For $300 I'd just be tempted to pick up a regular console. (I didn't know they charged monthly fees for online play, though. That seems a little dirty.)