Kevinjc,
I recently played a round out in Phoenix Arizona while at a work conference. I didn't expect to play so I didn't have my clubs with me and had to rent a set of Callaways. The attendant gave me a sleeve of the new ProV1x's with the rentals and I must say that when I connected (I'm not that consistent) there appeared to be a noticeable increase in distance over the ProV1s I normally play. I'm not talking 20 yards, but I bet 5 yards is realistic.
The unknown variable, however, was the warm and dry desert air. I've never played in this environment so I don't know for sure if the additional distance was attributed to the balls or to the humidity. Could have been a little of both I guess.
For what it's worth...
Jerry