I'm one of those folks who tend to feel the 3rd gen S&W traditional double action pistols are decently rugged, reliable and accurate.
Then again, I've carried one or another issued & personally-owned 3rd gen gun for more than 20 years, I've been through the 3rd gen pistol armorer class 4 times and have had the opportunity to help support, maintain and repair several hundreds of them over the years.
I own several 3rd gen S&W's based upon my experience with them as issued guns over the years, too.
The significant number of problems I've encountered with 3rd gen guns have been caused by the users. Most of them have involved either neglected guns, meaning those not cleaned and/or receiving insufficient lubrication or excessive use of solvents and lubrication.
Insufficient lubrication and uncleaned speaks to itself.
Excessive amounts of solvents and lubrication that can work their way into places where they shouldn't go and are probably best avoided. Some examples of problems that may occur when exposure to excessive amounts of solvents and lubricants are involved include:
Contaminated firing pin channels (light-strikes)
Contaminated extractor recesses (failures to extract or feed, depending where the accumulation ends up, at the front or the rear of the extractor)
Sluggish operation or movement of critical parts (bad fouling & accumulated sludge)
Magazines that are never cleaned and become contaminated (dirt, sand, grit, fouling, solvents, etc) can cause problems, too. So can those which are abused or damaged (which is why I prefer to buy new magazines).
The factory recommends armorers replace the magazine and recoil springs in duty guns either every 5 years or every 5,000 rounds fired. (Personally, when it comes to the compact or subcompact models - like the 3913, 6906, 4513TSW, 4040PD, CS9, CS45, etc - I prefer to err on the conservative side and replace the recoil springs more often.) No reason to subject the gun to unnecessary battering by not replacing the recoil spring st least as often as the factory recommends for duty guns.
The extractor and sear release lever (involved in decocking) are fitted parts, meaning they generally require some filing when being installed and should be done by someone who has the knowledge and tools. Fitting an extractor requires the use of a bar gauge (dimension check for Go/No-Go tolerance range) and a force dial gauge (extractor spring tension).
While it's not uncommon for the extractors in well-used guns to eventually become work-hardened and chip or break (we started seeing some small increase in them out at 12-15+ years of service), it can happen sooner if the gun is abused by improper loading. Improper loading means by dropping a live round into the barrel's chamber, instead of loading it into the chamber via the magazine, in the intended manner. Improperly loading a round directly into the chamber and dropping the slide forward causes stress on the extractor hook when it slams against the case rim and has to pivot out & around the rim from the rear. No reason to abuse the gun in that manner.
The company has made some continuing improvements and refinements in design, materials and manufacturing over the years since the initial introduction of the 3rd gen models.
The most easily noticed changes were back when MIM hammers, sears & triggers were introduced. Introduction of MIM hammers resulted in better triggers for the most part. When it came to the older machined hammers you never knew whether a particular hammer was going to be smooth on the surface where the sear nose rubbed during the initial DA stroke, or rough as a shale outcropping due to a dulling cutter. Other spots could vary, too. The MIM hammers are more consistent. Ditto then sear noses and trigger "ears" (prongs which engaged in the drawbar head's V-notch).
The slides were also changed to eliminate the rounded breech face shoulders (going to the straight cut breech face) and to accept a wider barrel tab (rear of hood).
Ever notice the somewhat "shiny" line surrounding the edges of the feedramp and barrel chamber mouth in a newer production 3rd gen gun? This was done because the barrels received an electro-chemical "polish" during production, with the barrels placed in a fixture and the rear of the barrel dipped into a solution.
Lots of little changes were introduced at various times, too. Things like longer ejectors (faster ejection & less potential for stress risers/broken tips due to a change in design), plastic disconnectors (smoother movement and better tolerances - no more 'long tail disconnector' issues, etc), improved extractors (hooks, bevels, tolerances, etc), improved drawbars ... and machining changes inside where it's not normally seen by regular owners & users.
The TSW models introduced still more features and subtle manufacturing & design changes over the years of their production. Things like delayed unlocking (reduced felt recoil with more pressure drop before the barrel unlocked from the slide), larger/thicker box-type frame & slide rails instead of the older stepped rails, and rails on the frame's dustcover (better accuracy), some continuing production changes when it came to major components and even smaller parts, the loaded chamber inspection port in the barrel tab. And other things.
It's a shame that the age of plastic service guns has caused a trend of moving away from the metal-framed guns, which are understandably more expensive to produce. While S&W will still produce the 3rd gen guns for established LE customers (who they can't persuade to buy the new plastic model line
), the days of production strictly for commercial sales are probably gone for the foreseeable future. (The 3rd gen production was moved to their Houlton, Maine plant within the last couple of years, where the .22's, Walther PPK's and SW1911's are made.)
The all-steel models are a bit heavy to carry around for 8-18 hour days (meaning the 5906, 4566TSW, etc). The aluminum alloy framed guns are lighter to carry, although the felt recoil is a bit more noticeable in the lighter guns. Just depends where the individual wants to draw their own line in the compromise of carry weight versus recoil dampening weight.
Overall, the S&W 3rd gen guns are among those I enjoy owning and shooting, and I still trust them as retirement weapons.
Just my thoughts. I could go on talking about them for hours. (And they aren't the only platform for which I've been trained as an armorer, either.)