Greetings and welcome to the forum. Better is subjective. Without getting into the caliber debate, i would say put them both in your hands and choose the one that fits and feels better to you. Other considerations between the two you mentioned are:
P220 - Single stack mag (thinner grip width)
- only one caliber of ammunition to purchase
P226 - Double stack mag (wider grip width)
- with the .40, you can purchase conversion barrels in .357SIG (and use the same recoil spring and mags), 9mm (but you'll have to purchase a recoil spring and mags) but you'll have options for up to 3 guns in one
Those are the primary consideration, IMO, before you decide which to get. I have both, but mine are quite old (without rails) and as my P226 came in 9mm, I would have to purchase a slide as well as a recoil spring and mags to fire any other caliber. Any other questions or concerns, just ask. Good Luck which ever you pick. You won't be disappointed.