Chad and others,
Keep in mind that, although the chambers of the smaller caliber L/K-frames are smaller, the cylinders are smaller too. The material between the chargeholes is not really an issue here (make sure you get the holes chamfered though, 'cause that DOES make a difference). Reloads aren't that much harder on an L-frame. I think the one thing that DOES make a reload harder on an L/K-frame is case length of .38 special/.357 magnum cases (extraction). But, since we're discussing only short rounds here, I don't think it will make a big difference. As a matter, I think I'd pick the 686 in .38super (and that means something, coming from a 625-loony). You have the reloading gear. You're familiar with the cartridge. And the gun IS softer to shoot.
But, whatever choice you make, in the end the gun will not make the difference
Good luck choosing