I bought my Roku for Netflix only - I have zero interest in Amazon or MLB.
It has worked perfectly and MUCH better than I expected it to for the few months I have owned it ... until October 1, 2009. I didn't even know it had HD capability when I bought it, so you can imagine how tickled I was when I hooked it up and received HD programming!
Since October 1, it still works perfectly until around 5 PM est, then it starts working perfectly again around 11 PM est. During this time frame, the quality is so bad that I can't stand to watch it on a 60" HDTV.
Of course Netflix claims there is no problem on their end. I beg to differ .... it is clear to me that they are not providing enough bandwidth during prime viewing hours. I can only speculate as to whether this is intentional or a result of increased usage. Given it started on the first of a month and is following such a set schedule, I vote they are doing it intentionally.
I know this isn't Roku's fault, but given I bought it just for Netflix, I guess its going to get eBay'd
I am located in Delaware on Comcast cable with very high download speed even during the problem hours posted .... also, I have watched some of the Amazon 2 minute free previews and the also work perfectly during these times.
Edit: Another peculiarity ... when I first start to watch something during the problem time frame, it will buffer and start just like normal. Then it switches to rebuffering in less than a minute and takes a very long time to start again. So long, I have just been turning it off.