I'll answer your question with a question.
What sized gun do you intend to buy?
I ask this because the size of the gun will greatly affect how the increased recoil of the .40 affects you.
Don't get me wrong. A G27 is far from intimidating. But your recovery time may be significantly longer with that compared to a 26.
In contrast, a full sized 22 may recover nearly as fast as a 17. (Also full sized, but 9mm)
Around 2000 I was convinced I wanted a 27. I was going to pocket carry it, so I wouldn't be using he pinky grip mag extension. Fortunately I got the opportunity to fire the 27 and the 26 side by side, prior to buying anything. The difference was astounding. With the 26, I could put 2, 3, 4 shots into a human sized target at defensive ranges very rapidly and accurately. Double taps were a piece of cake.
With the 27, I was much much slower to get back on target. Double taps were unacceptably strung vertically.
I picked the 26 because it allowed me to put more lead down range more accurately.
Don
p.s. if you are going to carry one of those little glocks with the pinky extension, you might as well get the 19/23 or at the very least carry it with a 19/23 mag and a sleeve.