Cranks are a lot faster, if you are stringing a 16x19 it may make a difference of 5 minutes or more. Cranks are also extremely accurate. Many say you get a lower tension but that is not the complete truth. With a calibrated crank you get exactly what you set it at. If you set it to 60 lbs you get 60 lbs every time it locks out. The problem is it happens so quick the string does not have time to stretch. if you want a higher tension set it higher or pull twice simple as that.
I have the ability to drive people crazy, not sure if I was born with it or I learned it but I'm damn good at it.