I realize this is an old thread, but I just noticed it.
I was (and to some degree still am) a M625 .45ACP shooter for both USPSA and ICORE. But I finally "bit the bullet" and got a M627 after USPSA implemented the new rule to allow 8-shot revolvers (minor PF).
Which case to use? I debated and debated. Short Colt, Long Colt, or "Mid" Colt? Many think the Mid Colt (which is a Long Colt or Special shortened to .9") is optimum. And many opt for the Short Colt.
I'm in the latter group; I adopted the Short Colt, perhaps primarily because I didn't want to spend the time to shorten Long Colt cases. And I'm quite, quite happy with the Short Colt!
The shorter cases, as noted by some here, DO load and eject faster. How much faster? I suppose that depends on shooter skill, but MANY better shooters do use the shorter cases (whether it be Short Colt or Mid Colt.)
My load: Starline .38 Short Colt cases, Fed small pistol primers, 3.3 or 3.4 gr of Tite Group and either Xtreme 147 gr copper plated (billed and sold as 9mm 147 gr .357") or Montana Gold 142 gr .357".
Works GREAT. It didn't take long to come to love the M627 and .38 Short Colt.