I replaced my first 4" 625-8 with the 625JM when it first became available, 2/05. As said, I tired of leaving DNA samples on the sharp trigger serrations - some fine emery cloth took the edge off quickly. As to trigger, it will break-in quite well to a smoother trigger. If you want a softer DA trigger, and recall that J M himself likes a stiff return spring for faster follow-ups, be prepared to be married to Federal primers, good brass, and meticulous cleaning under the ejector star - and of the moonclips.
Still want that lowered DA pull? S&W grinds the 625JM's strain screw as a trigger lightening step. The sharpened screw wants to go into the Wolff replacement hammer spring, whether regular or reduced, power rib hollow, effectively shortening said screw's length more - and further reducing the hammer energy. Even with Federal-only primers, I had ftfs with the reduced power hammer spring - until S&W sent me a full length strain screw. The full power Wolff hammer spring is an improvement over the OEM spring - and still permits other primers to function. I use only new Starline brass, having put away my .45 ACP sweepings for now (It's my only .45 ACP firearm!). Some of my revolver-only Starline brass has been reloaded 10-20 times or more.
I load .45 Auto Rim Starline brass with .45 Colt lead (Usually 255gr LSWC) for 'fun' - no moonclips required. If I have a revolver I will wear out, it'll be the 625JM. Yeah, mine is a keeper - as is this year's 'best buy' - my 627 Pro. They share the same height HiViz front sight, easily changed in seconds. I still bought a second one for the 627 Pro, of course!
Buy lots of moonclips (Ranch Products were ~$30/100 delivered.). The Brownell's nutdriver-style demooner is all I need. If you reload, Starline .45 ACP brass is $137/1k delivered from them. If you don't reload, Wally World had UMC ball ammo in brass for $82/250. It's a fun piece... and a great home protector. When quizzed by a range-friend why I didn't have a bottom-feeder with spare mags to defend my home from Zombies, I took this picture for him:
105 loaded moonclips fit in a metal .223 ammo can. I feel protected!
Yeah, I like the 625JM.
Stainz