686.
Mine is a wonderful gun, perhaps the most accurate revolver I've ever owned. It is a -5, so it has the MIM parts and frame-mounted firing pin, but that didn't turn me off as much as I thought. Trigger is slightly heavier than I like due to the firing pin, but still not as bad as most Rugers.
There are two other things you should consider (and this is just my opinion).
First, Ruger quality just ain't what it used to be. I say this as a very disappointed ex-Ruger man, having owned many, many fine Ruger sixguns in years past, as well as some current specimens of theirs that I feel are simply "junk". In short, I've seen some real quality control issues in recent Rugers. I've spoken of it extensively in the past, so do a search if you want.
I don't believe Smith and Wesson is having this problem. Of course, this could change.
Second, the "Rugers are built like tanks" mantra is somewhat mis-leading and not accurate in my experience. It is possible to break one. I have broken two Ruger revolvers through the simple act of dry-firing. Sure they can handle high pressures, but a chain is only as strong as its weakest link and I feel the Ruger has one in the cheesy 30-cent casting they call a "transfer bar". When it breaks, it causes a catastrophic failure to function, not a nice thing to have happen in some circumstances.
Also, the 686 should be even stronger since Smith added their endurance modifications in the later models.
Just my opinion, no flames necessary.
Please, ALWAYS USE SNAP CAPS!