The 4-3/4" balances better in my hand than the others, particularly when chambered for the 45 Colt. The reduction of metal in the cylinder and barrel because of the larger caliber makes a big difference, at least to me. I have two BP framed, pre-War USFS versions in the safe now.
I have to add, the beauty and history of the 7-1/2" (it was first after all) makes that a favorite barrel length as well. And the performance of the original loadings out of 7-1/2" single action is very impressive. My USFA Gunslinger (I hate that name) is just a delight every time I take it out of the safe.
I have been telling myself for years I should like the 5-1/2" barrel. It was the barrel length of the first SAA I bought when I came home from Vietnam in 1971. I've owned several of them and have USFA's so called "Artillery" now, but I just can't form a lasting connection with it.
Dave