Not sure what happened to the OP's original thread on this same subject... odd.
Cornered Cat is a very useful website (and it's also available in book form, if you want a hard copy).
But back to guns:
Accuracy is important, but I am going to disagree only slightly with Kreyzhorse: Reliability trumps all. (Kreyzhorse probably doesn't disagree with that argument; he just didn't address it.)
jimbob86 also makes a good point, in that if it is too uncomfortable to carry, you probably won't carry it.
Since the OP plans to carry this gun (I'm assuming in some sort of belly band) while doing some serious long distance running (she mentioned half-marathons), it will need to be light - which to me rules out SP101 and similar; it will need to be relatively impervious to sweat, lint, jostling, and shifting around during muscular exertion - which to me rules out things with exposed hammers, and most small semi-autos, especially anything with an external safety; and it will need to be reasonably easy to grab, under garments, with sweaty hands - which to me screams snubby revolver.
That pretty much narrows it down, for me, to the LCR if one likes Rugers, or the 640/642, 440/442, 340/342 if one likes S&W.
Of those, I'd go with the 642 or 442. Reason being, the AirLites are painful even with .38Special; the AirWeights are still relatively light, and aren't that bad with .38Special; I find .357 painful until one gets up to SP101 weights, and the SP101 is not a gun I'd want bouncing against me while running due to that same weight.
I know a lot of folks think, "I'll just practice with the .38, and use the .357 for defense - I won't notice the recoil when my adrenaline is up." This may be true, but that doesn't mean the shooter will be able to control the gun when the time comes. I'm a believer in practicing with loads that have similar POI (Point of Impact) and recoil to my carry loads; I don't like surprises.
I know I've put 100rds of .38 158gr LSWCHP through my 442 in a single session without any problems. I can even put a pretty good round count of the Buffalo Bore +P loading of the 158 through it with no ill effect.
Small .357's are just plain painful, and it's hard for me to shoot more than a handful through a gun that light.
Note: I can close the 167.5 lb Captains of Crush gripper with either hand, and am now working on the 190lb set. Grip strength isn't the issue. Small .357's hurt.