Rainy (Houston) weather kept me off the course for almost two weeks, but finally had a chance to try the prototype ball (red number) into play Saturday and Sunday.  All the following, I am comparing to the ProV1X I normally play.  

• Off the driver, the prototype ball felt slightly softer, it definitely flew longer... couldn't determine the total roll out since the fairways are still very soft. 
• Off a 17 degree hybrid, again, the ball flew longer, one time ~ 10 yards, and ~ 4 yards roll out.  Further into the round, I thought an off center shot would get dumped into a left side bunker protecting part of the green immediately behind; surprisingly, the ball carried the bunker, ~190 yards in the air... he old ball would definitely have bunkered; I'm not that good, the pin was back center.  With a 22 degree Hybrid, the prototype flew further by ~4 yards and stopped with ~1 foot roll out.
•  The prototype was great with long irons and short irons and wedges.  Slight to moderate more spin.  
• No surprises on whether it turns more or less that old ball, however, I did learn that on a purposeful hook out of trouble, the prototype ball is much easier to turn. I actually needed to lessen the amount of hook setup to produce the same trouble shots as the old ball.
• When needed, the spin is there for chips and pitches with more spin.    

I am very impressed with this prototype ball... I hope my thoughts are consistent with Titleist expectations, and that the prototype I played becomes the next generation ProV1X.

Bob L.  Houston, TX