My EDC is a 3913 Ladysmith (single stack DA/SA 9mm) that I bought new in the mid-1990s. I have several thousand rounds through it, and to this day the only failure of any kind was a single round of Winchester bulk-pack from Walmart that was apparently missing the priming compound in the primer; the firing pin smashed the primer nearly all the way down to the bottom of the primer cup and it didn't go off even on restrike. It is remarkably accurate for its size, reliable, the SA trigger is excellent (and the the DA trigger is good enough), and I like having the option of a manual safety. It is a little bit heavier than a modern polymer-framed gun of similar size, but not all that much more (aluminum alloy frame helps here), and the capacity is lower as a consequence of the thinner grip (only 8+1), but it's a great CCW gun. I once looked at a 6906 at a gun show, which IIRC is comparable in size but double-stack, and I think one of those would make a great CCW pistol as well.
I also owned and shot a 5906 for a couple of years (a CDNN police trade-in), but it was steel-frame and HEAVY, about 2.4 pounds empty and 2.9 pounds loaded. I used Mec-Gar 17-round magazines and it was absolutely reliable; I had exactly one failure to feed in that time, a round of WWB with a split case that was so out of spec it wouldn't fit all the way into the chamber. I was a little disappointed in the accuracy, in that it was slightly less accurate than my 3913 in spite of having a longer sight radius and longer barrel; I looked into upgrading to a match grade barrel, but the aftermarket for accurizing 3rd-gen Smiths just isn't there anymore. I eventually sold it, mostly because of the weight (nearly 3 pounds in the holster), and replaced it with a FN 9mm longslide that gives the same capacity, better accuracy, and an inch more barrel with only 2/3 the weight.
For history's sake, here's an early '90s S&W ad for the 3rd-gen pistols:
The G26 is superior to both SIG 239 and S&W 3913. It is a mute point because Glock now makes single stack 9x19 pistol.
I have quite a bit of experience with both the G26 and the 3913LS, and I personally prefer the 3913, although the G26 is certainly a fine gun. The 26 was harder to conceal, for me (stubbier but thicker, and for me the limiting factor was grip thickness), and I found it somewhat less accurate than the 3913 as well. I also prefer a manual safety on a gun that will occasionally be carried AIWB, which is especially convenient in the summer here in NC.