That much we can agree on. We also agree that the heavier unfluted cylinders are harder on the mechanism increasing the rate of end shake wear and stop notch peening. However, from my match shooting I think the increased stop notch peening is more theory than reality as long as you follow Miculek's advise to gently close the cylinder. He just does it without wasting time. Some of the competitors and instructors I see slam cylinders closed and pound down their ejector rods with unnecessary force.
I wouldn't buy an unfluted revolver if the same gun was offered with flutes, but unfluted cylinders do have one slight advantage: they draw smoother through my some what dated break front match holster. The cylinder spreads the spring loaded sides of my old Ernie Hill leather during the draw.
I wound up with an unfluted 3 7/8" 610-2 because the 2001 introduction of 3 7/8" barrels continued S&W's mid 1990s policy of not fluting 610 cylinders. Starting with dash one 610s all 610 cylinders were unfluted until flutes were returned at the start of or during dash 3 production. 610s were discontinued after the production run in which mine was made. After a few years 610s were reintroduced and officially cataloged in both 4" and 6.5". The pictures of 610-3s on S&W's website showed both the 6 1/2" and 4" guns with flutes. Those pictures were up for quite a while and all the 4" 610-3s I saw for sale on the web during that time had flutes. I was surprised the first time a member posted a picture of a 4" 610-3 without flutes. I was hopping another member or two would post pictures of fluted 610-3s.

Which ever was standard or more numerous, it's too bad S&W didn't make another batch of 4" 610s so you could have purchased one without paying through the nose. I'm sure you'll learn to like your 4" 625. That's what I wanted but couldn't find at a reasonable price so I settled for a 4" 610.