I have a Kimber Ultra CDP II that I plan to use for concealed carry. With +P defensive ammo (Corbon 185 grain +P JHP here) and an aluminum frame, control for follow-up rounds difficult if you are not prepared for it (the felt recoil). Additionally, as was said earlier, the shorter sight radius will make accuracy decrease for most. As far as 'bite' goes, yeah, it will take some time to build up a callous on the web of the hand, but once it has, you don't even notice it anymore....at least I don't.
The G27 is a great weapon. I previously owned one, but sold it to my brother for a concealed carry weapon before I left Oregon. He likes it a lot better than any of my 1911 frame weapons, and is a really big guy (6'5" 255).
So, I guess I'd ask you the following:
- Is there a specific reason, other than caliber, that you want to use something other than the G27? (the .40 S&W is a fine defensive round IMO)
- Are you having difficulty with concealing or accurately hitting the target with your G27?
I personally like the .45 ACP round, and ergonomically, the 1911 frame is very well suited to my hands. However, if there was another weapon, in another caliber that was even better suited to me based on reliability, ergonomics, and ability to conceal, I'd make the change in a heartbeat. BTW, I still own a Glock 23, and it was my primary off-duty carry weapon as a LEO back in the day. I plan to carry it in the winter when heavier clothing is the norm.