I agree with most of what Rob has said above, although I have found that I use my hammock less and less, despite that I get a much better sleep with it. Many (most?) of the campgrounds I have visited in Western Canada won't allow hammocks, citing potential damage to trees (ridiculous, I know). My hammock (Hennessy Ultralight Backpacker zip) deploys just fine in "ground mode" as a bivvy, but it does require carrying a sleeping pad and poles (I've tried using my bike to hang it, and it is less than ideal). Anyways, if I have to plan to use the hammock in ground mode, I find that I carry way too much stuff, and my sleeping kit ends up being twice the volume and 150% the weight of my ultralight tent. So I just carry the tent instead, if I know I will be hitting campgrounds a lot. Otherwise, I really prefer my hammock. I wish there were some better options to carry it all the time, but I just haven't figured it out yet.