I have quite a few 1911's - but only 2 Kimbers ....
One is a Gold Combat stainless, 5", out of their custom shop that is an above average gun / not a great gun. I dislike the series 80 stuff ...and the trigger isn't great / gun is about 5 yrs old I guess. The guns out of their custom shop are around $ 2,000 ( gold combat, match, raptor, etc ) - but they do get more attention than some of their other models.
One is a Tactical Pro II model, alloy frame, 4" barrel. The alloy frame is light / and annodized - but the finish doesn't wear too well. It would really be beat up if I had it in and out of a holster all the time. This model is around $1,000 - and the trigger was junk when I got it. I paid a local gunsmith to replace it all with a new wilson combat trigger and now its a very good gun ( but finish is what it is ).
In general - I would stay with a 5" gun / especially in .45 acp. I have fired 3" guns in .45 acp / and it takes a lot of concentration to shoot them well ( they jump around a lot ). A 4" gun is a decent compromise ...but I still prefer and carry a 5" gun most of the time. My carry gun is a Wilson CQB,
5" model, with armor tuff finish on it ....and its been a great gun. On the downside - is the weight. But in terms of size / I would carry a 3", 4" or
5" 1911 in the same IWB holster ...so it really isn't much difference / except a few ounces of weight.
My personal opinion is you should carry the gun you shoot the best / so for me that is a 5" 1911. I have a couple of 4" 1911's - but I really don't shoot them much / and I don't carry them at all ....thought I would / but I don't ...