Based on the owner's manual for the Tyros, I've found some good and BAD things so far:

Good: Song Auto Revoicing changes XG midi files to the better Tyros sounds - great idea. Master Multi-band compression has great potential, HD support up to 137 GB, and Song Position Markers (can be saved?) are nice features.

BAD: Here is comes... first I don't care for the ugly external screw-on music stand and speakers mounts that are certainly going to be problem when it's time to put the Tyros in a carry case. Then I got to Page 80: the Mega Voice "Catch-22" buried in the center of the manual: it says you can't select or play the new MegaVoices from the keyboard, but you can produce songs and styles using them??? If this is possible from the Tyros internal sequencer or style creator, the manual doesn't say. Maybe they mean you can do this from a software sequencer (I could tell more about this if Yamaha provided a MIDI implementation chart, which apparently is in a separate owners manual called the Data List). So what sequencer program does Yamaha recommend with this new next-generation keyboard... a new Tyros OPT panel with for use with Cakewalk Sonar? Nope. The new Yamaha SQ01 sequencer software? Nope. The answer is on Page 58: the only computer sequencer package mentioned anywhere in this manual is Yamaha's defunct XGWorks. Somebody want to guess how long it'll take Yamaha to release a Tyros voice definition file for a sequencer program that they have discontinued? This is bound to get ugly...