I know this is a question that people have written book upon book about but could someone explain the desirability and the reason for the desirability of certain Colt 1911's? As I dive deeper into 1911's I find myself drawn to Colt 1911's and I'd like to learn as much as I can about them. Let's stick with 5" .45 caliber guns. I see some for less than $1000.00, quite a few in the $1500.00 range, and some 2K+. Why? What makes one more desirable than another?