Actually saw quite a few of tehm on the slopes last season...all on Rossi/Dynastar sponsored riders (racers & free skiers).
The bacis Idea was to update te heel. The heel had 2 issues to watch out for. First, It could jam w/ snow on the sides or more likely it could jam & displace the plastic on the inside while using a tuning vise or boot. This was only an issue for me on one pair of skis ; I tried the swix vise & things popped out & needed to be fixed w/ the plastic forward pressure piece on the heel
Second the heel only had so much travel to adjust to a wide range of boots. This was not ever an issue b/c I'm done growing & a ski snob who does not share equipt.
Neither of these things is a real issue for the upper level skier on this forum. The new design claims to couple the heel better & has more travel to adjust. This should help shop folks & online retailers b/c it will be easier to mount/adjust & will not jam a easily. This system is not as easy but closer to how the marker does on size mounting.
I am really on the fence too here, we have about 8 sets now of pivots in the house. I have my 2 new skis that need to be mounted this season...I think I go w/ the pivot 14s again & give the PX seires a serous season of consumer abuse.