I have both. I have the Glock 27 in an IWB holster right now actually. I carry at 1 o'clock.. I got used to carrying the 27 so much that I forget sometimes that I have it. The same can't be said for the 23. It's a little longer on the slide and on the grip. Now, there are some people that swear by 23 and say they like this and that better, and the pinky grip on the 27 bla bla bla. Put a pinky grip extender on your 27 magazine and you're good to go. Love the 23 as a night stand gun, safe queen, or for plinking at the range-but not for conceled carry.