If I were to use a 1911 as an EDC, then I would go with the 9mm simply for the added capacity.  If I'm mainly using it as a range toy and BBQ gun, then I would go with the .45 acp.  I'm a bit of a purist and I like the classic feeling of firing 230 gr ball ammo through a 1911.  I'm sure the 9mm 1911's can be fun at the range, but I like using higher-capacity guns to plink with and I already have a few 9mm's that are my go-to range guns.  I'm sure I would feel differently if I lived in a state with magazine capacity restrictions.