I was a long time Pro V player up until this year. On a whim I tried the 330s and I won't be going back to the Pro V's any time soon.
For my game, the 330's are just as long, if not a bit longer. They hold the greens where I play as well as the Pro V's and they feel great around the green. The thing I like the most about them though is that they seem to be a bit more forgiving when I miss. Every ball is wonderful when everything is square and you hit them pure. The thing I've noticed with the Pro V's is that if you but a bit to much sidespin on them they tend to curve off the planet. Sadly I don't get to play enough to pure it every time so when I do miss the 330's tend to wind up in the 1st cut as opposed to the Pro V's which end up in the trees.
That said, the performance characteristics of the balls are getting more and more similar. It's more about personal feel and preference now much like it is with drivers, irons, putters, wedges...etc..