The 788 uses tracks 7 & 8 as a dedicated stereo pair. Useful for stereo inputs from a drum machine, synth, etc...
On the other hand, the unit has a whopping 250 tracks that you can assign and un-assign to the 8 track channel strip.
This seems very flexible to me for bounces and combining takes. You can only record 6 inputs simultaneously, but that's 6 @ 24 bit and it plays back ALL eight tracks at a time.
This actually is better than the Korg D1600 for 24 bit recording, as the Korg only can record 4 tracks @ 24 bit, but can play back 8 @ 24 bit.
The Korg may have the nod with their integrated CD and Fx's, but it is also not as flexible when it comes to virtual tracks as their are only 128 total tracks, and they are grouped in sets of 8 to each of the 16 tracks.
hope this helps,
-bruce