I think this has potential. Of the various iTunes alternatives out there, I like this one for several features. Primarily, it's nice to be able to set markers easily in order to repeat just snippets of a song. Also, both the pitch and tempo settings are exceptionally smooth. I would have expected some jumpiness when switching them, but no, they are flawless.
However, given that iTunes now provides gapless play, I'm pretty spoiled. I would hope that SSAudioPlayer can incorporate this feature. I'd also like to see it have some kind of equalizer or, ideally, to allow VST plug-in effects. Again, given that I use VolumeLogic, I'm kind of spoiled.