If you're worried about MKV support why don't you install PS3 Media Server on your computer, leave all your videos on the computer, and let the PS3 Media Server stream the content to your PS3?
PS3 Media Server will stream basically any type of video file you'll probably ever download. It auto converts the file for the PS3 at the same time it sends it to the PS3, so there is no long "conversion" process before you can play the file, its automatic and "instant".
I've been using it for a very long time now and nothing is easier.
PS3MS is a nice compromise, but is not as good as XBMC was. Having the player run on the PS3 as opposed to the PC avoids issues with crashing and the inherent loss of quality when transcoding. Crashes are rare, but having Ps3MS freeze and running down the hall to restart it is a chore. Also PS3MS has not been updated in 6 months ans still has some issues.