I have a 617 and a SP101. I think the SP101 is stronger and built a little better. My 617 has 3000 to 4000 rounds threw it and still seems good. The SP101 has only about 1500 to 2000 threw it but is still like new. I like to carry each of the guns. If I had to pick one it would be hard to decide. The 617 is a little fatter but they carry all most the same IWB. The 617 has a bigger grip to hide. For the pocket, the SP is not bad in a back pocket.