Although there has been some talk about various models being discontinued, both the 910 and the756ProII are still very much evident on the Icom America website!
The 9100 is billed as a satellite transceiver (I mean it does has a little button on it marked "satellite", so it must be....yes?) but in essence its a TS2000 clone (a shack in a box) and my fear is that because it has so many features packed in to it, its only going to be as good as its weakest component.
I will wait for those operators with vastly deeper pockets than mine to give it a thorough shakedown before I would consider trading in my trusty 910 - after all, "if it ain't broke, don't fix it!"
Sometimes I think we are a bit guilty of being "rig tarts" (quaint English saying meaning to be enamoured of the next shiny box that comes along to the detriment of our existing gear!)