Sounds like it's not that hot then. I don't know much of anything about them as I'm partial to WD boxes. My father in law just wanted something to watch netflix with and these are cheaper than WD's. I didn't know that you couldn't watch video off the SD slot, it doesn't as all he will use it for is Netflix and maybe youtube. Cheap was the main factor.
They just announced MKV playback locally and some other updates:
http://blog.roku.com/blog/2011/12/13/roku-software-update-rolling-out-on-roku-2-and-roku-lt/
DOH! sorry, its just the XS that can do MKV still...