Kim,
I have used a Hennessy Expedition as my primary shelter for 4 years.
The best feature is the bottom entry. You can enter and exit even with the fly hung very close to the hammock body. The closer the fly is to the body the smaller the fly needs to be to provide complete protection. I use a GoLite poncho for the fly.
The structural ridgeline is also a very important feature because I can get the correct sag the first time every time. Stuff sacks hung on the ridgeline with mitten hooks are an excellent way to stay organized.
The A-symetric shape means carrying less fabric and also it matches the shape of the poncho/fly.
The Claytor Jungle Hammock with a MacCat Deluxe tarp is an excellent winter hammock.
The Eagles Nest is a good picnic hammock.
Like all gear it needs to be matched to your style and the trip. Not appropriate for above timberline and desert hiking.