There's nothing wrong with the Stressfire reload, but the FBI reload is faster, and in competition (which sounds like what you're interested in), revolver shooters live and die by the reload. Some very excellent shooters don't use the FBI reload, but it certainly has it's advantages.
In competition, you'd be shooting a gun with a full-length ejector and ejecting .38 special cases, which are shorter than .357mags, so as long as you hit that ejector authoritatively, you shouldn't have an issue. If you do have issue, it's a user issue. Practice your reloads at home with dummy rounds in the speed loader and dirty (and not resized) cases in the gun. Practicing with only the dummy rounds can lead to a lazy thumb.
Keeping your gun (and chambers) clean helps, too. I ran plated bullets over Clays and never had an issue with my chambers getting sticky, even over the course of a long sanctioned match or practice session.
They make (or used to) CompIIIs for j-frames, but I really don't see the point, since the CompIIIs are really meant for competition (and 5-shot J-frames aren't). Also check out some Jetloaders (my preference). Slightly more expensive than CompIIIs, but IME, work a smidgen better.