I think, that there may also be "behind the scenes" software updates going on for the 950. I.e., that newer units get "different" software than earlier units as engineers find things to improve. For example, I have heard of at least 2 of the updates for the Rotel containg code to improve the steering to the rear channels.

BTW, the Sony TA-E9000ES was the same way. Fast and furious upgrades at the beginning of product life, and then they petered out as they finally "got it right".

Too bad there's no easy way to find out the "rev" of a 950...