No its a different animal altogether. No video wall or fancy features really - plays DVD files and ISOs fine. Remote is like the WDTV Live's with a few extra buttons and functions. The 550 remote doesn't work with it (more's the pity). I'm not sure I have any 1080P MKVs to test - will have a look. Nothing in the manual suggests they should be a problem though:
Cheers SSB. Will it play DVD's from SMB shares in the native format? The way it looks on the server is \\share\<movie name>\VIDEO_TS.