Didn't want to derail the 40 S&W thread
With some mention of the 357 Sig in the other thread, I figured it should have it's own discussion.
So looking at ballistic charts, a +p 9mm will push 124's ~1250 fps and 147's ~1100 fps. The 357 Sig will push 124's ~1450 fps and 147's ~1250 fps.
I'm curious how the added velocity fixes any of the 9mm's short comings?