The 659 vs. the 5906
When Smith & Wesson adopted a new nomenclature and implemented it along with its new third-generation models, the second-generation 659 became the 5906 - one of the widest used, most dependable law enforcement sidearms ever.
Admitted of favoring S&W, I'm uncertain as to Glock's numbers in and pertaining to LEO usage so it may have unseated the 5906. Yet, the gun was just a flat-out heckuva gun that took a beating (literal) and kept on ticking.
Of course, and as it did with a great many of its third-generation handguns, S&W "uglied up" the 5906, putting aside the beautiful wood grips to the favor of black nylon (some people say "plastic") grips that also cut the price, somewhat. The 659 with wood grips and a nicely maintained stainless steel exterior looked fine.
Yep, that all-stainless steel gun tends toward being a bear, especially when loaded, and weighs 39.5 oz.
Introduced in 1982 with SN A782700 and discontinued in 1988, one aspect will bump the collector-market price a hair or two: a short-wide extractor (SWE), which after only enough guns that today makes 'em "scarce," the 659 dropped the SWE to the favor of the extractor most famously implemented in the Model 39-2 and Model 59.
According to the online Blue Book of Gun Values, a 90-percent 659 is worth in the neighborhood of $300 and ranges upward to $475 for a 100-percent example.
Personally, I have two Model 659s, one with the SWE and one without. The SWE has a matching box but both have been carefully preserved and locked away for a rainy day.
Once again noting my bias of nearly all things S&W, I wouldn't hesitate to add another.
Good luck.
Later.