The S910 has dozens of new synth sounds. It's voice palette is similar to the Tyros 2. The S910 has about 250 more voices than the S900. A little over 30 are special voices (the ones that have ! in them). The rest are additional voices in all categories. There are some great voices among them, many of the synth sounds are featured in the styles, and many of the other voices are layered in the OTSs of certain styles.
Beakybird