With better video (12bit/216MHz vs. 10bit/55Mhz), a lower profile (3" vs. 5.2"), and HDMI output (for your future-proofing needs), I'd say thay Yamaha trumps the Onkyo's 1-disc advantage. The Yammy also does 24bit/192kHz audio if that's of any concern.

Looks like you've got a winner.