The 686-4 is already drilled and tapped for a scope base and is easy to add a red dot or scope.

I have a 27-3 8 3/8" and couple of 686-4s , a 2 1/2" and 6". For a gun that is going to be fired often with Magnum loads I would probably rather have the 686 4" over the 28 4". For a collection investment the 28.