I would mostly echo both lori and jim's sentiments, believe it or not.. I have hammocked for probably 7 years or so. 90% of the time I am hammocking. it is heavier than just taking a light tarp, but more comfortable, so you have to decide where your tradeoffs lie personally. I will take the hammock, and use it as a bivy if I expect the odd place I can't hammock. Example, I'll take the hammock on west coast trail on vancouver island even though I know there will be one or maybe two places I can't hammock and will end up sleeping on the sand under the tarp.

OTOH, high stuff above treeline, where I'm spending much of the time exposed, no, I'll take a solo tent that can deal with some wind and being set up without trees.

Really, depends what you're doing and your goals and comfort level. I personally still end up with the hammock in my back 90% of the time. (Speer 8.5C, or Warbonnet blackbird, with simple square 8x10 silnylon light tarp.