But, the PX-716A has some pretty fancy specs for CD burning too,
What can it what the PX-712A can't with CDs?
Nothing that I can see, but what was there to add? The 712 has all the features of the Premium, as far as I can see.
But, from what I can see, the PX-716A appears not to support CD-MRW. Or Multi-session, for that matter.
Compare the "Recording CD Modes" from the PX-712A data sheet:
Track-at-once, Disc-at-once, Packet Write (variable and fixed)
Multi-session, Session-at-once, CD-MRW (Mt. Rainier)
to those from the PX-716A data sheet:
Track-at-Once, Disc-at-Once, Packet Write (variable and fixed), Session-at-Once