The nice thing about the newer Smiths, like the -5, -6, & -7, is that parts and service will be in production and available for them for the foreseeable future. Your great grand kids will the able to "mind meld" with S&W customer service and have a replacement part "teleported" to them instantly on their "replicator" for their -5.
The older Smith parts, not so much. Many of the key parts, the one ones most likely to break, are already out of production -- hammers, triggers, rear sights, etc. And will likely never be made again.
S&W refuses to work on older Smiths already, like pre WWII guns, due to no parts. How long before they refuse to work on pre MIM guns? Will the millennials of today leave their safe spaces and grow up to be the skilled revolver gunsmiths of the future? If not, who will keep the old -4 and below M686's running 50 years from now?
When I got it it had rubber grips, did a little work on a guys 586-1 that had original wood grips and he said he would trade me rubber for wood, well that made me happy and made my gun look better!
