The SP101 is stronger than the Model 60, and is also more comfortable with full-house rounds: but it's also heavier and bulkier. For holster carry, this isn't a problem, but for pocket carry, it certainly is!
I prefer the SP101 myself, if talking about .357 Magnum, simply because I find the J-frames difficult to control under recoil with such a powerful round. However, I shoot a 442 and 642 with .38 Special +P and don't find any problem. I guess the best thing to do would be to shoot both with your chosen carry load and find out which one you shoot best. Buy that one, and dress accordingly.