Your thread seems to be just in the right place, since it is a question many of us had.
From my perspective, jelqing has more of a controlled stretching effect, giving you a rightful sensation about blood flow, pressure, and penile resistance. Pumping is more of a all-rounder, as vacuum works in all directions, thus giving you a consistent pressure and less variables, if you monitor pressure. However, both techniques can be quite dangerous if you do them wrong enough. Jelqing, especially without proper lubrication, can easily turn into an ULI, while you penis is not yet prepared for hard expansion. The result - red dots, popped veins, etc. Bathmate can also be dangerous, especially with high amount of pressure.
One thing I’ve learned over the course of my body experimentations as a semi-professional footballer before, and an active person since I could walk, is that your body needs anywhere from 14 to 30 days to get accustomed to stress levels, if they are consistent. Learn to listen to your body, embrace what it tells you and don’t work against that, despite your deepest desires to stretch your penis to the moon. Believe me, I also fall into the “Grow faster” trap, but I tame myself, relying on my sports discipline.