I have SSK barrels with 4 port M-N-P, Arrestor, and a 416 Taylor with their fish gill. Although you didn't mention the Mag-na-port option, I thought I would comment on it. The M-N-P is not quite as effective in reducing muzzle flip as the Arrestor. This equates to an Arrestor equipped barrel to stay down with all the remaining energy being directed straight back at your hand. Of the two, I find the M-N-P more comfortable/tolerable to shoot, especially off the bench. In comparing an Arrestor equipped barrel to the fish gill, I have a SSK Encore 500 S&W barrel with an Arrestor, and I have an SSK Encore barrel in 416 Taylor with the fish gill. I'm shooting 350 grain bullets in each, using about 40 grains of powder in the 500, and 68 grains in the 416. The fish gill is much more comfortable to shoot. The multiple baffles/vertical surfaces of the fish gill help negate the rearward thrust. It does have a little more muzzle rise than the Arrestor, but it dumps so much gas that it is not bad at all. If it were me, I would go fish gill. My 2 cents.