Bryan,
I'm hitting the same driver as I did last year- Titleist 975L-FE, 8.5*. I'm looking forward to trying the newer 983 series Drivers. My irons are the same as well- Titlest 690CB. The largest difference I notice is with the driver, 3 wood from the tee, and long-middle irons. I think you'll see less of a jump in distance in the shorter irons due to decreased swing speeds with those clubs.
Tom,
Like you, I saw some increase with the original Pro V1 over the previous ball I played, the Professional, but I really think there is a more pronounced jump between the Pro V1* and the new ProV1x. For me the ball flies a bit lower with the irons and is much better in the wind than the previous model I used.