Don't forget: There's an in-progress Rockbox port for the iFP-7xz series. It's *very* early right now, but far enough along that I think there's a reasonable change it'll get to a working point with time. Right now, it can *sorta* play WAV audio. Which is, y'know, a lot further along than "Y'know, it'd be neat to have Rockbox on an iFP-7xx"
So while that's not a short term reason to get it (as it's useless right now) in the long term it may lead to the iFP-799 being a rather more impressive device.