Just had the opportunity to try out the 2013 Pro V1X test balls last month. I was given a tube of test balls by Titleist Singapore and I have to say that I am really impressed with them! Definitely I got more distance and roll on my drives.
As for spin, I noticed the previous Pro V1X had more backspin as compared to the 2013 balls.
Nevertheless, I love the 2013 balls and can't wait for them to be available on the market!