I had scissor springs on my seat for a day and swapped back to barrel springs. I'm 6 ft 175 lbs, and the scissor springs were bottoming out on me. I don't know if it was just the springs I had but I didn't like them. I also prefer the look of barrel springs. The only problem I've had with barrel springs is installing them. The space between the coils doesn't give you much room to work with.
Looks only, I would do barrel. However, with the frame style not being a softtail, I never thought that spring seats looked right on Sportsters. Look into choppershox.com too.
I have 2" barrel springs on my 48 with stock shocks and scissor springs on my Hardtail xs650 and have never noticed much of a difference. I am 5'10 and 185 (all muscle of course). Like sf said, mostly just which look you prefer.
I tried scissors first, went to 3'' barrels, then to 2 inchers and changed how they were mounted, moved them forward about two inches, I can feel them work.