I have used a Dryad from Terrelogic.  The call words are "suspended sleeping system" for the net and you will find others under that moniker.  The Dryad has a cot-like frame so the bottom is firm and flatter than a hammock.  In our area it is easy to find two solid trees close together (or one huge tree, like an old limby white pine) to hang in.  In other areas it can be a problem to find the right trees for set-up.  The Dryads have about a 250 pound load limit. 
One of my friends had a Hennesey hammock but didn't like the central, bottom ingress/egress door.  I remodeled it for her so the door it came with is sewn shut and I put a long zipper on one side between tent fabric and mosquito netting so she could get in/out from the side instead.