I have a Glock 23 3rd Gen. It is absolutely one of my favorites. I've carried it more than any other pistol. I have a Crossbreed Supertuck holster for it. Some people do not have a preference for it because it can be snappy in a lighter frame.
The 40 S&W was developed to give law enforcement greater stopping power than a 9 MM. If a HP round fails to expand you still have a bigger bullet to make a bigger hole.
Do a Youtube search on Hickock45 Glock 23. He can hit a gong with his at 230 yards.
If I were to venture a guess, I'd say they are about #4 on the popular list, behind the 19, 17, and 22.
The 19 and 23 frames are identical and the slide is nearly so. I started to buy a 23, but .40s&w ammo is stupid expensive for what it is when compared to 9mm and 45 acp. So I got the 19 so I could have some cheap plinking.
I like mine. Only problem I have is deciding between my 27 and 23 each day cuz I can conceal them almost the same. I have a 19 but for some reason (I know it's probably in my head) I can't seem to trade 180gr for 124 gr in same size gun, and I know they make 147 but the velocity is crap. Also +P is same kick as .40 anyhow so I laugh when people go to the range and shoot 115gr all day then carry 124 +P expecting to be accurate...
In god we trust, all others we monitor...
I have owned many Glocks...all the .40's and more. All the .40's I've had were good and the G22 was the best for me. Over the years, however, I moved away from the .40's but would not hesitate to own/carry one. One thing to watch for in any Glock is frame flex, for lack of a better term. If you buy one that shoots consistently to the left or right, send it down the road and buy another. If you find one that shoots to the sights - keep it!