VVYK3D -
If you have shot and liked the P226 in 9mm, you will also like it in .40. At least I do. I shot the 9mm version extensively, and when I transitioned to the .40 I was a bit surprised at first because the recoil was snappier.
It is not, however, uncomfortable, nor is it uncontrollable. It is a very easy transition to make. And if you look at the numbers, the .40 is a more powerful cartridge.
I have found my P226 in .40 to be plenty accurate, one ragged hole at 7 yards rapid fire, somewhat larger at 15. Sorry I can't comment on 25 yards from a rest under controlled conditions, I don't shoot that way. I can get the same level of accuracy out of a P229 in 9mm.
It would appear that the gun is more accurate than I am. Or maybe I am just a sissy-boy. In any event I would recommed that if you are plinking or target shooting, go with the 9mm because the ammo is cheaper. If you are looking for a defensive weapon, go with the .40.
Enjoy the beast, regardless of which one you get.