Mike, my reasons may not be common for everyone, regarding liking the S910 over the S950 as the latter is a terrific instrument with some decent upgrades (for some, however) over the former.

The S910 felt much the same to me as my Tyros4...just one of those special instruments that had everything I needed, and devoid of relatively less useful features like audio drum based styles which have very limited editing ( I do a lot of style creating/editing) and possessing the most usable sounds.

The S950 offered only more SA sounds (no SA2) and the SA sounds on the S910 covered all the bases for me. Styles were basically the same as S950 (with the exception of the aforementioned audio drum based styles) and since I only use the Vocal Harmony/mic input for vocoding and as an audio input (for audio recording) for my buddy's electric guitar (or my CS-01 mono synth) the basics were all I needed.

I went to the Tyros4 because of the the more substantial build quality, the FSX keybed (with aftertouch) and the SA2 sounds, which are another whole level (to my ears) above SA voices. Plus, the drawbar organ section and internal rotary were another notch up on the scale, and, since I have the expansion card, I can load in more sounds.

Of course, getting a great deal on the T4's price sure helped.

I suspect the next S-series will address any issues with the present S950 as the S910 did with the earlier S900.

Anyway, that's my story, and I'm stickin' to it.

Ian