I have two pre series II Kimbers with 4" barrels, and three Sig 1911's one with a 5" barrel, and two with 4" barrels. They are all high quality guns, (my own opinion) accurate, and none of them have ever failed to function, with whatever ammunition I've used. I prefer the use of a bushing in the Sigs, as opposed to the reverse-tapered barrel in the Kimbers, as the Sig require no tools, to take 'em apart. The Sigs have an external extractor, as opposed to Kimbers' internal one. The Sigs have the "Swartz-type" hammer block, where my pre series II Kimbers do not. It's been my experience that often some feed issues are exhibited by 1911's with barrels under 4", and often with hollow point ammunition.
You're in Michigan, I'm two hours south of the Indiana-Michigan line. If you'd care to make a day trip, I'll be happy to let your father-in-law shoot 'em both and decide which he prefers.
Only when our arms are sufficient, without doubt, can we be certain, without doubt, that they will never be employed....... John F. Kennedy
Life Member NRA Life Member Marine Corps League