Hennessy are generally highly regarded. I spent a few nights in one. They are pretty well made, etc. The one negative thing I hear most about them is that they are very slippery inside and everything seems to end up in one big ball in the center by morning; especially if you haven't been diligent in setting it up very level in the first place. I found this to be somewhat true when I used one. Bottom line, hammocks have pro's and con's just like tents when it comes to light or ultralight back packing. You might consider the Clark Jungle Hammock as well. They are my preference.
This is a good sight for reading in depth reviews. They've done a lot of Hennesy reviews, but there are others to give some perspective. What I like about this is that the reviewers give their bios and experience levels:
http://www.backpackgeartest.org/reviews/Shelters/Hammocks/