Just finished setting one of these up in my bedroom attached to a 42" Plasma. The reason I bought it was 1) Price - $90 plus tax, 2) 5ghz wireless n, 3) MKV playback with DLNA, 4) Netflix/Amazon Prime VOD/Hulu+ support. I have been searching for an all in one solution for these items and have tried nearly everything, including boxee box, appletv 1/2 (jailbroken and not), and wdtv live. While all these have their merits, none have provided the complete package. I was considering a roku as well, but it does not natively support mkv streaming.
So far in my testing, this box has finally succeeded in combining all the features I wanted in a very reasonably priced package. Picture quality is great on all sources, amazon/netflix/hulu stream hd wirelessly without problem, and playback of mkv has been nearly flawless. The only videos that are having trouble with stuttering are high bitrate 1080p, and this is likely due to wireless limitation not the box itself.
I do find the menu navigation a little on the slow side, but not unbearable.