There is a lot of hype surrounding Ruger - which is a fine gun, no question about it.
Oh, Lord Jesus there's no hype surrounding Smith and Wesson! BWAAAAA, ha, ha, ha!!!!!!!!!!!!!! That's primarily why the MSRP is so high on 'em, hype.
Lots of folks buy the name alone. It could be a POS RG revolver, but if it has the Smith and Wesson logo on it, it'll still bring $500 from some folks. I do think I'll take an investment casting over an MIM part.
Actually, friend of mine has a 686 and I like it very much. It is quite accurate. But, at the time he bought that gun, I had a Security Six I'd done a trigger job on and it was MUCH smoother and lighter than his 686, so it don't take much to get the Ruger's trigger "un-tort lawyer safe" and put some feel back into it. I didn't even buy springs, did it by carefully testing the hammer strikes and trimming the hammer spring until I started to see the indentation on a CCI primer start to get lighter, then I stopped. I never had a failure to fire after that, either. I slicked up the moving parts simply by using fine lapping compound on pivoting parts. Out of the box, it was a little stiff, but quite shootable. After the work, it was AWESOME! I don't think I'd wanna try to do the 686's trigger, just let a smith do it.
I'll say, though, you are well armed with either revolver. What I say about preferring the Ruger doesn't mean I wouldn't buy a Smith. I'm sort of still weighing the MIM parts thing, though, and the lock. I really don't think the lock is that big a deal, but I've heard other opinions and I haven't actually had a Smith with a lock on it to take apart to see how it works.
Heck, the DA .357 I have now is a Taurus M66, not as strong as either the 686 or the GP, but it's also lighter, a K frame sized gun. I don't like the extra heft of the L frame/GP guns. I had both that Security Six and a M19 in the past. This Taurus is the first one I've owned that was exceedingly accurate with either .38 or .357 loads. Neither the Ruger nor the Smith would shoot very well with .38 special stuff. While this is not a big deal to most, it is to me because I wanted these things for outdoor use and small game. I felt they should group better than 3" at 25 yards with wadcutter stuff. The Taurus shoots 1" groups with both wadcutter and a 140 grain Speer .357 load that my other guns liked. No, strength was NOT the first thing I was looking for in a DA revolver, but if two guns are of equal heft on the belt, I'll choose the stronger one. You wouldn't want a M60 to weigh 40 ounces in your pocket, would ya???? Different application totally, apples and oranges, and when you buy one, you accept the fact that it will not stand up to a lot of heavy .357 loads.
If I wanted another Smith .357, I'd get a 66 for the same reasons I like my Taurus, lighter and easier to tote, but large enough for outdoor accuracy.