I've had, and carried:
*S&W Shield (.40)
*Walther PPS M1 (9MM)
*Glock 43 (9MM)
*Kahr CW 9 (9MM)
*Kahr CW 45 (.45, yep)
and a lot of larger guns. Out of the box:
*Shield is dead nuts reliable, needed an APEX kit to have a tolerable trigger; carries very well
*Glock 43 is dead nuts reliable, needed a trigger upgrade to have a tolerable trigger and upgraded sights (I got Dawsons); carries very well
*Walther PPS was dead nuts reliable, shot like a larger gun and carried very well. Usable sights out of the box, but trigger was fairly awful
*Kahr CW 9 was dead nuts reliable, had a great (but long, DA) trigger out of the box and usable sights. Carried very well
*Kahr CW45 is VERY susceptible to 'limp-wristing' (to the extent that shooting it one-handed makes it genuinely unreliable, regardless of grip), has a great trigger and usable sights, but just slightly too large to carry conveniently
For whatever that's worth-
Larry