I have two G23's, both of which are gen 3 models and one of them is my primary carry gun for both open and concealed carry. An excellent .40S&W platform, the Glock 23 is considered to be by a well known write in the gun culture, the best combat sidearm you can carry.
I have not fired nor handled the gen 4 models much so I am not in a position to offer comments on the new gen 4 models. I suggest you peruse Glocktalk.com for more info on this.