Barring mechanical failures, at least you know the bugnet is closed using a zipper. I'd be leery that I left an opening in the velcro somewhere letting all the little buggers in. I would opt for a double-tab zipper, too.
"Well, it's one louder, isn't it?"
There's a lot to be thought through here, not just zippers vs. velcro but also neo's total aversion to velcro (I, too, hate the way the hook side grabs everything, particularly bugnet) and Hector's use of a Hennesy. Zipper failure is a real concern but thinking back on the zipper failures that I've had, at least half of them have been at the end where the zipper separates. That argues for permanently closed ends, which in turn implies a non-removable bugnet, which in turn eliminates the possible use of a sock. Then I got thinking that just the gas to get me to and back from where I do my canoe camping costs far more than the materials for a hammock (exclusive of the suspension, bugnet, and other accessories.)
So now I'm thinking, cut the side velcro from both the hammock and the bugnet, sew the bugnet to the hammock on one side, and use the 8-ft zipper on the other side but hand-sew the starting end of the zipper closed to minimize the stresses that cause end-failure of the zipper. That would be the hammock for bug-season use.
For Fall camping, my favorite season, make a separate insulated hammock, i.e. with a built-in underquilt, saving the cost and weight of the upper half of a conventional underquilt, but without a bugnet. Somewhere I read that insulated hammocks were common before separate underquilts took over. Can anybody point me to online discussions about them?