Think the hammock zipper location is inconsequential? Think again. Where the zipper is sewn can make a big difference in ingress and egress on a hammock.
When I sleep in a hammock, I most often lay in a diagonal with my feet shifted to the right of center and my head shifted left of center. Some hammocks are designed with an orientation one way or the another, and the placement of the zipper (for models that come equipped with a zippered bug net), determines in large part how you spin or rotate to get into position.
Getting in a hammock, I recommend you spread the hammock out and sit first, laying down on your torso and swinging your feet in last. Getting out follows the opposite approach: swing your legs out and sit up. Depending on the placement of the zipper and the orientation of the lay (feet right or left), you may have to spin a little or a lot to get ready to lay down or get up.
My personal preference is to have the zipper attached to the side of the hammock closest to my feet. In this way, entering and exiting is faster and easier because I have to spin less to get into position, since the angle I need to turn is smaller.
With the zipper on the head side, I have to spin or rotate my body much further, extending my legs high over the center ridge of the hammock, before I am in position to lay down or get up.
Now that the science is out of the way, and regardless of the tradeoffs of the two different zipper placements, what is your preferred location for a side zipper?