It's funny to hear all of the bashing on here. This is a very hacker-friendly device. What's to stop you from putting a custom ROM like Cyanogenmod on it? Nothing. In fact, I think that it is encouraged to mod the heck out of it.
AppleTV's sell for $100 also, and they don't play games or come with a controller. Also, how may $100, small form factor, low power PC's out there can you find that play games that are being actively developed today?
Shelling out $100 a year for the new version of this isn't necessary. Just like it isn't necessary to get a new phone or PC each year. However, at $100 a pop, it wouldn't be that bad either. When you buy your new one for you family room, move the older one to your bedroom TV for web browsing, video streaming, or light gaming. Heck, you could probably also make an older one it into a decent NAS with a USB hard drive.
The Ouya isn't a competitor to PC, Xbox, and Play Station games in the sense that you will get much better performance from the big boys. But, just like the Wii was a competitor to everyone else and spread marketshare, the Ouya or something like it could take the market by storm.
When Minecraft exploded in popularity, it was ugly and buggy. However, it was cheap, open, different, and fun. Ouya is the first 3. If it can get the "fun" part down, the doors will swing open for Android consoles.