I would recommend leg swapping instead of dragging them behind. Your tendons will thank you. It is not necessary to use your biceps. Just keep you hand stretched. It saves muscles and energy.
Comparing the under rope style with upper style:
ADV
- way easier to get there
- time saving start
- you can breath freely
DIS
- more difficult for the hand grip
- it can feel painful for Achilles tendons, you can burn them by dragging
- when your grip fails, you fall down back first!
I would prefer this style when my hands are fresh with strong grip. I would also use it for shorter traverses. Good rope condition (dry and thick) are important too.