I find that the shoulder-slap is the most difficult part of recoil to deal with.. now, I've never been beyond my 8.5lb 375H&H, so that's a bit less than you guys, but everything else that Ray mentions has been a non-issue (well, except the whole jaw-smack... but that was a one-time lesson I learned QUICKLY).

my upper back and neck are pretty strong, and I've got some royally hosed-up rotator-cuffs. however, I would also note that proper fit of the rifle is several dozen times more important than any recoil pad could be!

good example: my 20ga Ithica 500 o/u (field) will tag you good if its not JUST right to the shoulder. my 12ga Ithica 700 o/u (trap) is a total pussy-cat... both have recoil pads of similar design, and are within 5-years or so on age.

for me at least, the guns with more LOP seem to be much less fatiquing to shoot... don't really know why, as I don't especially have an exaggerated frame (5-9, 180, mostly torso)