DR DAVE  This is a great little app for simply playing MIDI and making quick changes to tempo, instruments, etc. My only qualm is the price. $25 is too much for a simple player / editor, and I think its strength is as a SIMPLE editor. The UI is fine for what I need to do. I'd say to put it on MUPromo with a 60-80% discount and sell a whack of them. For $10 or less it would be a no-brainer.   
(Version 2.4)