Yes, I have several and really like them (thanks to a neighbor who sold me her used ones).
The only drawback is they are expensive new and they are somewhat heavy. Not too heavy in my opinion, just heavier than most regular saddle pads.
They also will not make up for an improperly fitting saddle. My horse would still get white hairs until I got a good fitting saddle.
But, out of all my saddle pads, these are my favorites. I think the felt probably helps as much as the gel. If I didn't have my Impact Gels, I would probably buy a really good 1" wool felt pad.
But they are definitely good pads. Especially the ones with the felt. I have seen ones that just have a Navajo blanket top and they aren't as thick as the felt ones. I have both 1" and 3/4" thick Impact Gels. I like them both. I probably use the 3/4" more often because I also like to throw a wool Mayatex blanket underneath the pad to keep it clean and because blankets are easier to wash than pads. So I never have to wash the Impact Gels that way.
I really like them better than the Professional's Choice air rides. I think the are rather thin and don't provide as much protection. But I am a trail rider so I like a good thick pad because I ride for hours and hours.
To sum it up, I really like Impact Gel pads, but don't expect them to fix a saddle that doesn't fit well. ( I don't think anything will.) But if you just want a good pad, they are really nice!