I have a 6" 66-6 I love, IL and all. My 5" JM 627PC V-Comp has a sweet trigger. My 5" h-l 686+ is a keeper, too. The very last one I would part with is the last one I bought - new last spring - and only a month or so old then:
I'll take my 627 Pro over a Python any day of the week. An N-frame, it'll handle, like the K-frames (13/19 & 65/66), any standard SAAMI spec'd .357M. The 627 Pro also handles 8 at a time - moonclipped, if you like. It's spring loaded front sight allows tool-less sight changes in seconds. It comes with a slicked trigger of sorts, but an S&W trigger job isn't that expensive. Decent wood grips help, too - the Miculek's shown are on my JM 627PC now - the 627 Pro sports Ahrends 'retro targets' now. You could buy a new 627 Pro, HiViz sight, Ahrends grips, have a S&W trigger job, and buy some ammo for less than a fair at best Python - with who-knows-what having been shot from it. Works for me... but I am not a Colt fan.
Stainz
PS Re the K to L frame 'improvement'... it's a thicker front frame, allowing a larger OD forcing cone, and a taller opening, permitting a 7-shot cylinder (and 5-shot .44 Specials...). The gripframe is the same as a K-frame. Additional 'out front' mass, to keep the muzzle down, is found in the predominantly full lugged barrel. It was thought that fc erosion would be a problem with lite (110-125gr) fast loads in the K-frames. Normal SAAMI spec'd loads 140-158gr+ were never a problem. An eroded/cracked fc simply means a replacement barrel is needed. Don't fear the longevity of a K-frame .357M!!