Don't know if my review would be of much value, I put it on a pretty soft recoiling 6-7PRC with a braked suppressor. It's a bit more comfortable to shoot than the factory pad. But I didn't have any issues with the factory pad. The Backfire was just the easiest way to gain some length of pull. That it's better than the factory pad is just a bonus for me.
I'd say it's on par with others i have (Limb saver, Kickeez, Pachmyar etc). This based on feel- I haven't shot them on the same gun.
It may very well be quite noticeable on a heavy recoiling rifle.