I had a set on my centerfire rifle. They're not any better than the XTM panels in terms of grip, but since you're putting one on each slot you have a bit more flexibility in placement.
I ended up taking mine off and going to XTMs on the bottom rail and the rubber ladder covers on the sides, so far I really like this compared to index clips all over. I also was using matching hand stops from LaRue and wasn't a fan and went back to a vertical grip.
LaRue setup
Current setup. The one on top has foliage XTM panels on the bottom, I didn't have an black and didn't want to cut a ladder before I tried out this setup, but I really like the slight color contrast.