The action on my pre lock, 7-shot, PC 586-5 L-comp is better than almost all my other pre lock 6-shot S&W's. Only my 19-4 rivals it.
My 686-4+ has a very sweet action as well. It is slightly different........I think it is the visual of the cylinder turning faster.....or something. Still a very smooth action, and no worse than any of the 6-shots, to me.