Good question.
Prior to a few months ago, the smallest gun I normally carried was a Glock 19.
I have a Sig 365 but have no difficulty concealing the Glock 19 which I can shoot quicker.
In Jan (this year) I got a Glock 17.5 and really liked it, much prefer the gen 5 grip over gen 3-4 and the 17 grip better accommodates my hand than a 19.
I'd been carrying the 19 in a simple kydex clip-on and with a loose fit shirt (as pictured) the grip did not unduly bulge AIWB.
I've been shooting a long time and the 17.5 made me feel like I was in my peak 30 years ago with the ease that I could shoot it quick & accurate.
I wanted to carry the 17 but am anal about not obviously printing; the solution was a holster with a claw to help push grip toward my body.
Having a claw on the holster made concealing the 17 no more difficult than the 19 that had been my minimum for the past 4 years.
Glock 35.4 top - Glock 22.5 center - Glock 17.5 bottom
View attachment 1078867
I liked the 17.5 enough to get the 22.5 and am pleased with it.
The 22.5 has a thicker (heavier) slide than previous generations of Glock 40's - subjectively recoil is on par with the 17.
If I was going to enter a shooting competition I'd take either the 17.5 or 22.5 - (30 years ago, I won a "Top Gun" competition with a 17)
If I have to defend myself its like a competition on whether I stop the threat(s) before incurring serious or lethal harm; I carry what I'd take to a competition.