I like fast line speed so you don't run over the line once the winch gets you moving again. Nothing worse than stopping and getting stuck six times on a long slick pull because you had to keep stopping to let the line spool in. A fast winch lets you keep crawling up. The other thing it does by keeping the slack out is save you when you slide back. Sliding for 15 feet till the cable stops can break the cable or not stop you from going over or getting in bad shape. It's an expensive option to get a fast one but if does as I described for you on the side of a dangerous mountain it's cheap.