I'm not really sure why, maybe it's the proportions of frame to barrel length, but to my eyes there is just something special about how a revolver with a 4-5 inch barrel looks. Under 4 inches they don't look as good and when you start getting over 5 I find them less appealing.
As for shooting one, I definitely shoot them better when they have longer barrels and the best I've ever shot any revolver was years ago I had a Ruger Redhawk 44 w/7.5 barrel that shot extremely well but aesthetically I'll take them with 4-5in. barrels over anything else all day long. It wasn't particularly practical but even my S&W 500 is a 4in. model.
I need to quit looking at the pics of that Pro Series 686 because every time that I do it makes me want one!