Josh Hirschmannwrote a review of POC VPD Air Leg on September 25, 2018
Familiarity: I've put it through the wringer
Before you purchase these, consider what you're using them for. If a majority of your time will be spent on downhill riding without much pedaling, go for a burlier pad. If you're looking for a light, comfortable, minimal pad because you're spending most of your time pedaling it's going to be hard to beat these. I had the previous version (not a real sleeve, had a tightening strap ontop) and really liked them. I absolutely love these... there was no real break in period, I forget they're there when I'm riding. The protection is adequate, again this is the Air series, it's meant to be minimal. You want something burly look at the rest of the POC lineup.
I got the size Medium (I'm 6'3 and 185 lbs) and don't have issues with them sliding down. I do keep the top of the sleeve tucked underneath the bottom of my liners. If comfort is your goal the POC Air should be on a very short list of options to look at.