Roku is beyond awesome. We've been using the same one for 2+ years. I was worried for a bit that it would be your typical made from china get rich quick no service and bail device, but they have risen to the challenge:
1. consistent updates and new features.
2. We can do search in our Netflix account right on the television ( I don't know if other devices can do that but it's pretty awesome). No need to run to PC to add stuff to streaming queue.
3. Great UI - doesn't look cheap and navigation is easy. My GF loves, loves, loves the Roku cause it's so easy to use.
4. Picture quality is DVD quality or higher for the most part: The first year or so there were occasional stops and starts and compression quality would vary. This was due just as much to the connection as the netflix. After that, it's been near perfect every time now that we have very fast cable connection except I don't like Starz movies, they cheap out on compression quality.
5. More and more channels added all the time: we don't really play around with the other channels. Seems like there are more and more all the time. We just stick to netflix but it's cool to see all the different ones available. a lot you have to pay for though.
6. Customer service: they have a very active forum and very very good customer service.
Mind you we are still using the original and it's been rock solid the whole time. Roku gets my highest reccomendation. Kudos to them.