We have Roku 2 and Apple TV, the UI on Apple TV is better, esp. Netflix. Roku 2 is 1080p, Apple TV is 720p, but our LCDTV does such a good job upsampling 720p you can't really tell.
Roku 2 has access to a lot more content, but the experience of surfing channels is kind of fragmented. The included Angry Birds game and motion remote rock tho!
I agree that each content provider developing their own digital distribution system would be inefficient and confusing to the consumer, who desires a simple, centralized menu and search function to locate and view content.
It's nice that so many websites offer some kind of streaming video, but the friction of moving from site to site, each with their own navigation and search functions of varying quality, seems like as much trouble to most consumers as getting up and walking across the room to change channels on their TV.
Netflix has done a good job in aggregating content, although I don't believe they have a format and business model that is sustainable into the next decade.
Roku 2 has access to a lot more content, but the experience of surfing channels is kind of fragmented. The included Angry Birds game and motion remote rock tho!