There seems to be a lot of confusion about this...I asked a similar question

To keep it simple, buy a sleeve of the new Pro-V1. Compare it to your current -1x on course. If you aren't amazed, stay with the -1x. Regardless of numbers, it is how it performs for you. Chris2009, Chuck Z, and myself all used the ball at Pinehurst, we have 3 different swing speeds, (100+, 90, 80+), played in different groups, and all were amazed before we even got off course. This is the first time for me that I found a significant difference between releases of any Pro-V ball. I've been using the -1x to try to get down the fairway (I'm the 80+ driver speed), and the new Pro-V1 gave up nothing on distance and the softer feel made the short game easier to control. If wasn't 24F and snowing outside my window, I'd be picking a dozen today.

I love the new V ball. I have playing the Prov1 for a number of year because of the spin and based on the recommendation of the Titleist fitter. The new ball is longer in my opinion, my driver speed is 93mph (I am an older fellow at 70 and got to play the senior tees) and won the long drive contest with that test ball at the TT Invitational. Like Don said get a sleeve of each when they come out and test them to see which fits your game best and go from there.

I have played the 2013 V1, then the 2015 V1x when they made it softer. I have always preferred the softer feel off of the V1 off my irons, however when testing the 2015 it seemed like the V1x went about 8-10 yards longer off the tee. I just picked up a dozen 2017 V1 to try on my Fla. trip next month, it sounds like it may be the perfect ball for me, softer feel with added distance.

Thanks all of you, good feedback. I bought the ProV and love it.