SMPlayer is just MPlayer with a nicer interface. MPlayer has no problem with OGM and MKV containers, and it has already been ported to the hardware. You will be able to play OGM videos with multiple audio / subtitle tracks.
In that vein, how's MPlayer's subtitle support? VLC doesn't do a great job (the font color changes but that's about it), whereas MPC + ffdshow + Haali Media Splitter does better.