My first carry gun ever (also first gun ever) was a Glock 26. I got a G26 over G19 because I was concerned about printing. I changed to a Glock 19 later that year when I found that the additional grip length didn't really matter with concealability as much as I thought it would. Since then I've stuck with Glocks because changing over to a different manufacturer would be a huge effort in replacing my multitude of Glocks, spare magazines, holsters, magazine carriers, and spare parts, with only the possibility of minimal gains, at best.
Now, for a smaller gun suitable for more formal dress (i.e. I have to tuck in my shirt), I've changed that quite a few times. I went from a Keltec P32 (second gun I ever bought and the first gun I ever sold, because it was a rimlocking POS), to a Kahr PM9, to a S&W 642, to a Beretta Nano, to a Ruger LCR to a Glock 43. A single-stack Glock 9mm was really what I wanted instead of a PM9 or a Nano, but Glock didn't make the G43 yet so those were the best substitutes I could find. The only reason I think I might ever change from a G43 is if a light-compatible Enigma is released and then I can just carry my G19 tucked.