I can't say that I'm unhappy with the Echo, but I will say that I'm somewhat disappointed. In any case, I'm sending mine back today. I'm on my 2nd unit and both have had issues with frezing and pixelation. The 2nd unit was far better than the 1st and was watchable to a greater extent. Still, I found myself turning it on only about once every week or two to see if there was a firmware update. Once it took the update I'd play with it for a bit and then shut it down. I kept trying to force myself to use it, but when the freezing started up and the image got pixelated I turned it off and went back to my WMC PC to watch it directly. Aside from these issues, it seemed perfectly fine for use as an extender.
Truth be told, I've never been a big fan of extenders. I don't like the lag in the menus and remote response has never been as good as it is on the source PC. I was hoping the Echo would be a huge step up, especially with respect to playing mkv files of Blu-Ray rips. I think a lot of us were hoping this would happen. In Ceton's defense, they never stated that this would be a feature of the Echo, but they also never said it wouldn't be either. If I had to choose between the Echo and an X-Box I'd have to pick the Echo, even though I don't have the same issues with the X-Box that I've experienced with the Echo.
I used to think there was a problem with my network since I'd see the dreaded "Network Issue" message show up on occasion. What puzzled me is every time I'd run the Network Tuner after seeing the error message it would always pass with flying colors. I beefed up the NIC in my HTPC with an Intel PCI-e EXPI3901CTBLK card and transfer rates are better to and from my HTPC than any other PC in my house, yet I still got the message. I used to get this with other extenders from Linksys, X-Box, and HP so it is extremely perplexing to see this with the Echo after the changes I made.
I'm currently using individual SFF HTPCs at several TVs and I was hoping the Echo would replace one of them and provide the same capabilities. Unfortunately, the lack of mkv support for BD rips and the other issues has removed it from consideration. I really had high hopes for the Echo and I still hope that Ceton can turn it into the product we were all hoping for. It's just not there yet, IMHO.