The gen 4 23 is not as snappy as the gen 3, but is still more snappy than a 19.
All one needs to do, to prove this, is a simple experiment.
Take a 23 and 19 to the range. Shoot the 23 first, go through 2-3 mags, then switch to the 19, and shoot another 2-3 mags.. May not notice much at all in the difference, other than a slight felt difference, and accuracy should be the same. The transition is easy, and requires no effort on the part of the shooter.
THEN, take the 19, shoot a couple mags, and switch back to the 23, and shoot a couple of mags. You will understand the difference in recoil, at this point, and how it affects shootability. It can be overcome, but is not the simple transition that 23 to 19 was. One must focus more, and put more effort into controlling the 23 after shooting the 19...
This is not saying the 23 is horrid, or needs to be only used by hardened veteran shooters,... only that there is a difference, and, yes it is noticeable, and yes it does have an effect on the shooter.
The 19 is easier to pick up and shoot well, when one has not shot for a while. The 23 is a great gun, too, just has a little snappier recoil. Both are great guns.
I have both, and would hate to part with either. Both have their uses/merits. If pressed though, and limited to only one, I must admit I would probably keep the 19.