I started shooting IDPA with a 2.5" 66 because that is what I had. I later picked up a model 10 4" but my old eyes had trouble with that little fixed sight.
I bought a 686 and when it went to S&W for warranty work, I had them do the slick up on it. I also added a Fiber Optic front sight. I liked the 686 and it is a good gun but I got a deal on a 4" 66-2 so I sent it off to a guy that does S&W work and had the full treatment done to it. I added the Weigand front sight base so I can change front sights but I use the black patridge front mostly.
I use a Kydex Holster and Ready Tactical holders with slightly cut down jet loaders.