I have an 8 3/8" 500 (original configuration, with the integral compensator) and a 4" 500, with the interchangeable compensators. The biggest difference in recoil is from weight, with the lighter gun having greater felt recoil, no matter what the compensator configuration is. Of course, to feel the difference, you have to be shooting loads light enough to show it - with heavy loads, the recoil is at levels greater than you can feel a difference. My experience is that the compensators for the 4" gun (with the holes on the side and top) simply result in more muzzle blast reflected back at the shooter, making it rather unpleasant to shoot with light (350 grain or so) bullets at high speed, especially. The long tube gun is much more pleasant to fire with that ammo, as the muzzle blast is not felt to the extent it is from the 4" gun. An earlier poster beat me to the punch on the modified compensator insert that 500 Magnum Nut built, as I saw his ad on the forum just a few minutes too late! That 4" would be much more pleasant to shoot (although not as "mean" looking) with a non-compensated barrel. I'm not very recoil sensitive, but, with some loadings, the compensator design on the 4" gun (same comps on the other gun you're considering) is a pain when it comes to muzzle blast. I much prefer shooting 420 - 450 grain bullets at almost any proper loading in this gun (actually, makes it fun to shoot), and stay away from the light bullet/high speed loads. Hope this helps.