From my experience with JSP out of 357 mag handgun, they act more like FMJ ammo then they do any hollow point. Of course if you hit bone, it mushrooms but at handgun velocities, if you miss a rib you may get FMJ- like performance out of it, which is not ideal. Without the hollow point to generate hydraulic pressure to begin opening in soft tissue, the JSP can sometimes not expand much at all.
In 357 Magnum and 44 Magnum, I just Use plain Ole Hornady XTPs (158gr and 240gr respectively)and they expand reliably every time, and get good penetration, the 44 has sometimes exited the other side. The 357 I don't believe ever has.
My next choice in line after XTPs would be standard weight LSWCs of hardness 15 -18 They also do the job very well on deer sized game.
I personally don't see the need for JSP in handgun rounds when there are XTPs and LSWCs out there, out of handgun velocities that is.
I could see the merit of JSP ammo out of rifles/carbines with higher velocities to achieve great mushrooming and deep penetration.