I've got a 315, nice gun, very well balanced, comfortable to carry and shoot, light enough for all day carry, heavy enough that recoil isn't a problem.
The 386 is a bit larger overall being an L-frame (the 315 is a K), but the grip frames are the same size. It's an ounce or two heavier, around 24oz, I think, recoil shouldn't be too bad with .357mags, certainly the gun is strong enough to handle as many as you're willing to put through it.
IMO, if you're not interested in shooting .357's buy the 315. It'll handle the hottest .38spls (I load mine with Buffalo Bore) is a little easier to conceal and a bit more comfortable to carry than an L-frame, even one of the same weight.