I tried a HH Backpacker for a few nights here in California and decided to return it to REI. First of all, finding the right trees seems a hassle out here. It's probably a completely different story along the AT. I posted a question about using a hammock in the Sierras on several forums and heard from a guy who said too often you'd be above the treeline, or the trees were wrong where you'd want to make camp, or you might be in a treeless meadow. This confirms what I've seen.
Also, at least with the Hennessy, it was a bit too claustraphobic for me. If I play with a hammock in the future I'll try an open top design.
And I sleep cold, and keeping the bottom side warm is a big production. For the weight of the hammock and underquilt, I can carry more ground padding and get the comfortable (enough) sleep that checking out the hammock was all about in the first place.
See you all over in the ultralight forum in the future. Thanks for the help along the way.