I have a 617. It's a great gun. I can comfortably shoot .357 Magnum Winchester Silvertips in it. It's Bulky though. Its a good belt gun but too fat for the pocket. The SP101 may be too heavy for the pocket for some, but it could be done. I don't have one but I have friends who do, and they all love the SP101. Between the two, I'd pick the 617. Close to the same weight, and ya get 2 extra shots.