In a plastic frame gun, I've found the .40's recoil more than the .45's because the .40's are in smaller frame guns. And the .40's tend to not hold up well, where the .45's do.
I watched a 40 Glock whip a big burly SRT type's azz for three days on a Roger's Range. They gave him a 9mm Glock and he started hitting plates.
