Yes, the shorter is less obstructive when performing anything where your torso contacts the ground. The thickness of the weights also plays a role along with where the weight is loaded on the vest. Being able to switch between loading front/back, high/low, center/sides is helpful for switching between different movements like push-ups and sit-ups for example.
The best is a plate carrier with weighted plates like the ones from Rogue. Second best in my opinion is something like the MIR airflow.
