I recently posted chronograph comparisons of .38spl, .38spl +P, 9mm, 9mm +P, 9mm +P+, .38 Super, and 9x23 Winchester using my 9x23 360J, a 637, a Taurus 905, a 9mm Beretta Cougar, a 9mm HK USP, and a .38 Super 1911.
The 9mm slays the .38spl out of a properly chambered snubby (Taurus 905) and still trounces it pretty good out of my rechambered gun, in spite of blow by.
IMO, moonclips are the only way to fly. Way faster than speed loaders and easier to carry.
Here are my comparison results -