I recommend the G19. I have and G19, G23, G22 Gen 4, and a G26. In Glocks, for me, the recoil of the .40 is very sharp (the Gen 4 helps reduce the recoil) so I shoot the 9mm Glocks much better. My pistol chart:
9mm: Glocks and M&P
.40: SIGS, H&K, and M&P
I like the Glocks a little better than the M&P for all the after market items and that I have about 15 Glock Armorers at work. I can set up a Glock exactly the way I want it. I carry a department issued/required SIG 229 .40 on duty but I carry a G19 off duty.
The best thing I can tell you is shoot both of them and see which one YOU like the best.
I have both and rarely shoot and carry my G23. The last time I carried it was when I went hiking in the mountains. I also have a 9mm conversion barrel and a 357 SIG barrel for it but found that I spend too much time dicking around with barrels, mags and ammo…time I could be using to practice hitting the target with my G19.
I’d recommend the current Gen3 G19-in either the regular or the RTF2 frame depending upon your taste/desire/climate.
I’d consider a Gen4 G23 (actually, I’ll probably get a Gen4 G32 in .357 SIG with a spare .40 barrel when they become available). I think that the Gen4 modifications are optimized towards the .40 cartridge’s characteristics, both in terms of platform performance and longevity. The 9mm Gen 3s are good to go as they are.
Other than for rather specialized needs (i.e., wilderness carry/increased penetration) I think that there are currently available 9mm cartridges which’ll do pretty much anything required in a handgun defensive cartridge-for less money, less recoil, and in a smaller platform.
I like the G23 as a carry gun over the 19 for it’s superior effects on target. The 9mm barrel I just picked up to give an added flexibility while traveling since 9mm is so much more common than .40. (I’ve even seen it for sale at the Gas Station in some places!)
I expected to have all kinds of problems due to the extractor geometry (per internet experts) but I’m actually coming up on 1K now failure free. To me it’s “proven” and while I still run a lot of .40 and carry in that mode, it’s nice to have the option.
Recently, I picked up a second threaded conversion from LWD and I’ll see if the reliability is still there running suppressed…
I have both, and typically carry the G23, backed up by a G27. For me, the number one reason for this is that I’m required by agency policy to carry issued ammunition, and our issued ammo in 9mm is TERRIBLE stuff, commonly referred to by other LEOs as “less than lethal” ammunition. Truly miserable.
I would, however, still carry the G19, if, in my case, I didn’t shoot the G23 just as well. My G23 actually shoots tighter than my “Austrian Proofed” G19. When it comes to recoil, I can tell the difference, but, my five-shot, five-yard, 5"-target groups show an aggregate time of .78-.79 seconds for five shots with the G19 with no “dropped” shots; and aggregates of .81-.82 for the G23 with no dropped shots. To me, this makes using the (in my agency’s case) significantly more potent .40 S&W caliber a “no brainer.”
If I could choose my own carry ammunition, I would carry the G19, without a doubt, because it IS easier to shoot - I don’t have to be so conscious about “riding” the G19 as I do the G23 when I’m shooting fast. I also notice that, at the end of a long range day with my G19, I’m looking for more ammunition to keep shooting; at the end of an equivalent day with the G23, I’m looking for Motrin!