Frank, I have the KeyB Duo Mk111. The Numa has the same sound engine as it's predecessors, the Mk1 and Mk11. The sound is very good but the quality is not quite up to the quality of the KeyB. If you're really interested, I suggest you go over to Keyboard Corners at this link.
http://forums.musicplayer.com/ubbthreads.php/forums/18/1/The_Keyboard_Corner

You can get solid information from some actual owners over there.

chas