I have made the switch to Pro V1s this year and have been experimenting.
I started off buying OEM Pro V1s and obviously I got the best balls with this. I then began experimenting with X-outs and refurbished balls.
I could definitely notice a difference when comparing the OEM ball to a refurbished ball. The refurbished ball just does not have the some consistency from ball to ball. I am sure that this is because you are not getting the same year, model, or run of ball like your getting in the OEM package. The refurbished balls gave me a bad impression and it only took 1 dozen to decide I wouldn't buy them again.
I then switched to the OEM X-Outs and had pretty good results. I have bought 4 dozen X-Outs so far and I only found 1 tiny paint imperfection on 2-3 balls. Most of the balls could pass as brand new mint condition. The X-Outs played very well for me and are very consistent. My only complaint with the X-Outs is I'm never sure what's going to be in the sleeves. I have gotten Pro V1 and Pro V1X.
I prefer to play a Pro V1 over the V1X and feel I have noticeably different results with each ball, so I am thinking about just sticking with the OEM packages of Pro V1. I may continue with the X-Outs since they are usually less than $30, but only for practice rounds.
When I am playing a serious round, I ALWAYS want to put an OEM Pro V1 in play.