But, let's be honest here. Is it likely that the S910 has the same quality DAC's that the TOTL Yamaha has? Or that the samples may be exactly the same length and compression?

I always noticed, when playing say a G1000 right next to a G600 (a friend has both) that the exact same patch sounds a LITTLE bit different from one to the other. A little thinner, less forward, more brittle, less warm, whatever. My friend now has an E60 and a G70, too (he's an inveterate collector!), so I might get the chance to A/B them, too. But from reports at Roland-arranger.com, I think some DID mention a slight perceived thinning out of the sound.

Maybe Ian (who has likely had them next to each other in a store, played through the same speakers, etc.) could comment about whether there is any difference in sound? It's probably slight, but I would be quite surprised if an arranger about $2000 less than the TOTL sounds IDENTICAL...