In my area, the Glock 45acp cal are going for $570 and the model 20 Glock (10mm) is going for $625 new price! I like the model 27 & 26 but I also like being able to get my hand on them securely in one quick motion, having a good grip on the weapon. Something I really could not master with that shortened grip.
I went to the Glock 21-SF for carry purposes, using my other 10mm Glock as a back up tool.
I personally believe the 45acp is a better "stopper round" up close within 21 feet. It is also hard not to like the idea of 13 rounds in the 45acp weapon.
Now for those that don't realize or have knowledge of the fact, I was shooting 100 feet today at the range with a Glock 20, 10mm cal making head shots on the target. This weapon needs not to be raised to score hits, just aim and fire. The 165 grain bullet gets there in a hurry and shoots very flat. Holding middle of the head sight picture, the Glock 20 put all hits eye-level on target or middle of the head on the target. YES! The 10mm Rocks N Rolls em in a hurry!!!