I've had an ATV 3 for over a year. Worthless IMO. Never use it. If I could jailbreak it, I would probably use it.
My personal project this weekend was to JB my Apple TV 2 once and for all to see what the hype was about.

(in a good way)
I have XBMC running on there with 1Channel, iceFilms, and Navi-X. Can also play any media off of my media server to the Apple TV. This is seriously the greatest thing ever, and I'm mad at myself for being too lazy to do it sooner. I never understood why JB ATV 2's were selling for like $300+ on eBay...now I do. I dare say the breadth and actual content of video available via the above sources not only provides you access to just about any movie or TV show you could reasonably think of, but also alleviates the need to VPN or worry about torrenting files, downloading and storing them. The quality is not top notch in all cases, but is good (in some cases is really good), and I was shockingly surprised at how high the quality was on Navi-X channels that folks live stream.
I know the other boxes/configurations are good in their own rights, but if you have an Apple TV 2 and the patience/time to investigate a setup like this,
it's worth your time. I had some learning curve snags with the JB/learning XBMC's quirks for the first time, SFTP vs. repository installs, testing video quality on wireless vs. wired, etc. to tinker with, but it's completely worth it.