Yup, IMHO the JV90 sounds warmer than the XP50/60/80. I have the JV1000 (= JV90 with a sequencer) and an XP60. Soon after getting the XP60, I started porting over patches from the JV1000, even patches with the same name on both keyboards, because they sounded better. BTW: I've sequenced with the JV1000 since 1993 and have never had any problems with latency or MIDI slop or the like, even with *very* dense sequences. Never once. Maybe it's just the individual keyboard?