We've got a couple of them. I just use them for Netflix and they work fine for that. They've got quite a selection of channels other than Netflix, for instance you can get your Amazon.com movies you've purchased digitally streamed through it as well. I've only looked at their free channels a couple of times. They had a couple of channels with really old B&W cheesy junk. Last time I looked though they had added commercials to some of them.
I think this is their whole list of channels:http://www.roku.com/channels/#
Copy and paste that whole thing into your browser since it's decided to only hotlink the first part of the address