Apples and oranges. Tarps can be very light (ex. silnylon) and easily staked out for a comfortable night in almost any weather. Hammocks (ex. hennessey hammock) can be strung almost anywhere and you can sleep very comfortably in alot of circumstances I'm told (although ensuring you have enough insulation below you can be a problem in colder weather). Hammocks also afford protection from insects that tarps do not (at least without added mosquito netting). Tents can provide most of it, bombproof comfort but at a cost in terms of weight. fwiw I've tried to split the difference, my favorite camping tent is the Double Rainbow tarptent by Henry Shires, it is light weight and provides room for 2 and plenty of room for one solo, and necessary mosquito protection where I live. There are those who will argue for their tarps and their hammocks and that's all fine, they are probably great for them, I like the compromise of the tarptent.