Having played both D10 and JV80 go for the JV80. Except from the drumtrack-sequencer there is almost NOTHING that a D10 can do which a JV80 cannot do, the exception is the ringmodulation. Basicly the two synths share the same concept "sampleplaying" but the samples on the JV80 is WAY better.
The sounds on the JV80 besides the synthpads are so much better. The JV-pdas are a little to "nice & clean" to my taste.