I haven't heard the RSP-1068 in my system, but I have a co-worker who has one. He needed a good bit of help getting it set up and running, so I got a chance to mess around with it. As morphsci has said, there are a few additional features (renameable inputs, Pro Logic IIx) - I suspect all of the 1068's extras will be in Outlaw's future pre/pro plus some, but it's still a ways off. The 1068 remote is not nearly as user-friendly as the rebadged SL9000 provided with the 950 - I convinced my co-worker to buy an MX-500 after a series of headaches and problems. The 1068 menu offers a bit more control, but the manual is dreadful. It drove me nuts, and my co-worker (who had no background with home theater gear) was completely lost.

The RMB-1075 is a pretty solid looking amp, but I think the 755 is certainly its equal sonically (plus offering more power per channel). The 770 will give you more power and more channels. The 7100 offers only slightly less power per channel as well as two extra channels, so depending on your needs it might also be a good candidate. I'm using a recently-added pair of M200's to drive my mains (which has worked out extremely well) and a Model 750 to drive the center and surrounds.

How do the two compare sonically? It's difficult for me to say - I heard the 1068 with a different amp (1075 vs. my Outlaw Model 750), different speakers (Nautilus 805's vs. my Paradigm Studios), different source (Sony DVD player and Meridian CD player vs. the Panasonic DVD player I was using at the time), and different rooms. My wife and I preferred our system's sound (the Rotel setup came across as harsher and a bit fatiguing), but since I never heard the system when it was using the Spectral pre-amp and amp that he had used previously I don't know if that was the speakers, source, or room (which was a pretty hard space). My wife cast a vote firmly in favor of the 950 at the end of the day, as she felt that it offered a better interface and she liked our system's sound more. My co-worker decided at the end of the installation that he probably should have simply called Outlaw for a 950/755, partly because he felt my system sounded comparable to his and partly because he was unimpressed with the service he got from his Rotel dealer (a dealer he's been working with for 20 years).