Let's first take a look at weight- and volume differences. I've weighed my tent and the hammock with tarp, not the mattress and the sleeping, which go with both.
Hammock and tarp weigh 2,250g.
Tent weighs 2kg straight (2,250 if I use the foot print; 3kg straight is I also bring the gear shed addition).
So there's a slight weight disadvantage in favour of the tent, but it's not a fair comparison as such, since the tent (an MSR Hubba Hubba NX) is a two-person tent. You'll definitely have to be good friends to sleep two in that tent, but still it's rated as a two person tent. But the correct comparison would of course be the Hubba NX 1-person, which I can't weight, but it's stated as weighing 0,93kg and it'll of course take up less volume as well.
But there's a definite volume-advantage in favour of the hammock, and that even goes if I only bring the tent, and of course that advantage only increases if I bring the footprint and the gear shed.
Another advantage to the hammock is that you're of course not dependant on level ground, and anoter significant advantage is that you're *off* the ground. One thing is cold, but another is bugs - particularly ticks, which are increasing dramatically in numbers. Years ago I often slept on a mattress under a tarp, but these days that includes anywhere between 2 and 15 ticks on you the following morning. So that's out of the question now. Just to be clear - they are *not* a problem in the tent either.
A great disadvantage of course is that you're dependant on trees or other "posts" to hang your hammock from, which you're not with a tent. But finding level ground can be just as difficult as fiding a tree, let alone two.
If you're in more "extreme" conditions, I imagine that wind can be a factor in the hammock. Rocking and swinging might be an issue, and you're more exposed. In the tent you're safe from the wind, and the hammock *might* (I don't know, I've not tried it) require a little more in terms of a better, more insulated sleepingbag to compensate from the lack of wind protection. The tarp can and do provide some, but not in the same class as a tent.
As for pitch-time, I think the are quite similar. When pitching in the rain, the hammock as a little advantage as you can pitch the tarp first, an then the hammock. The tent has to go up before the fly can go on, and that will expose the pitched tent to the rain, until you can cover it. And in heavy rain you have to be careful that a tent doesn't flood - not an issue with a hammock.
The MSR Hubba-series also has a little storage area in terms of small vestibules on both sides. You can't store heaps, but a small bag fits well in both sides. Of course much more if I use the MSR GearShed, but then we're also talking significant more weight and volume. The Amok Equipment tarp also allows you to store gear out of the rain, but it's not necessarily on dry ground after a shower. But then again, neither is the gear in the vestibule(s) of the tent.
All in all I think it's fair to say that it's a case of choosing the right gear for the right place.