The OP asked the difference between straight and back set ASL. I don't think too much, unless there the backset is over an inch. Backseat should be a bit faster.
That said, I have had different experience with string follow. I really like how pavan said it, not all string follows are created equal. I used to lift a lot of weights and developed a sensitive elbow ... String follow was easier on my body with both draw and release. I have shot Chuck Jones string follow, Nate Steen's and of course JD Berry's. They are very smooth drawing, easy on release, (not mushy at all) with surprising performance. I do not feel I give up anything with a string follow, but I gain a lot in comfort and shoot ability.
Maybe the difference for me is I have is a 29 1/2 inch draw, that does give me a pretty good power stroke.
Bob.