I did some testing last night. Connected to an 801.11n wireless access point.
First tried a 8.4GB MKV via Plex. 100%.
Second tried Battle Los Angeles which is a 11.3GB MP4. Again. 100%. Also via Plex.
I then spent the evening watching TV shows and stuff (also via Plex). I had the odd stutter which I think is attributed to my gazillion devices hooked up to the wifi in my game room. I am ordering a D-Link 4 port USB hub with ethernet to get the MK802 wired. Also ordering a Mecer bluetooth keyboard with touchpad to contract the thing.
There is a customised firmware available which enables you to control the device from your cellphone. This I will do this weekend and report back. The app on the play store is Droidmote.