Watching cops and civilians on the ranges around here (one public, two private, one commercial, 4 LE) the SIG is the more reliable of the two, less ammo/mag sensitive. Both are good enough, the Kimbers (and SAs) just seem more likely to be particular over what ammo mags they work best with. This Kimber/SA likes Wislon mags, that one does not. This one likes Gold Dot, that one does not, etc.
The avg 220 shooter is as good as the avg 1911 shooter, but the guys who work at it with the 1911 have an edge in shooting tighter faster. Most of the 1911 shooters think that is the edge that counts. The better 220 shooters are not that far behind, think the reliability is the edge that counts. More cops w the 1911s than 220s carried as approved options. The Glock 9/40/357s dominate as std issue, and some of the best shooters are happy/stick with them.
No best here, just what's best for you?