Kind of like trying to decide what Cadillac to buy isn't it? I also like both but give the Pro V1x a slight edge. If I was you I'd play the one I score better with. If there's no clear winner in there then all that's left is...do you prefer a red number or a black number? Gold or silver? There's no wrong choice here if all other things are truly equal.   

what is your handicap. Also do you like a lot of spin on the tee. Which performed better for you around the green?

They are both great golf balls! What you need to do is take a look at how each one performs with your "scoring" clubs", that is the ones you hit to most of the greens on the course you play. If you tend to miss a few more greens than you would like (who doesn't!) then look at how each ball performs around the greens. You decision will become very clear.

Personally I play the ProV1x. I prefer its lower spin rate to that of the ProV1. I find that when I play on a windy day the ProV1 is a bit harder to control. I also find that I tend to spin the ProV1 a bit too much off the wedges. The ProV1x was an easy choice for me.