I have an older, one of the first made actually,715's, a 686-1, and 3 28's, and have shot a 627 quite a bit. The 715 is the most accurate, by a small margin, of them all, but at 30-50 feet, it's meaningless. The 6" 28-2 has the best DA trigger of all of them, followed by the other 4" 28-2's and then the 686-1, the DW 715 isn't bad at all, it's just a little heavier and different feeling. I shoot it the best of all of them. In SA, the 715 and the 6" 28-2 are pretty close with the DW having the edge due to the shorter hammer travel, but it's not a big deal, to me anyway.
IMHO, the accuracy difference at any reasonable distance isn't enough to worry about, but I prefer the DW method of opening the cylinder, by far over the S&W guns. My first good gun was a DW 15-2, and I wasn't used to the S&W method at that point so I wasn't prejudiced against it as so many people are.