I moved up to the 6500 from the 6000 with no regrets. First a good trade-in from my dealer and secondly, a perception that the sound had actually been improved---less distortion, etc. sealed the deal. Maybe the differences were subtle, but present nevertheless. Comparisons of home recordings (CD's) seem to favor the 6500 to me. Also, no lock-ups which I experienced with the 6k. That's worth something. The workmanship and overall "feel" of the instrument seemed improved as well. I like the 6500 so much the new 7k will really have to be impressive to entice me to trade. But I'm willing.
Larry