I could write about tents and shelters all day. I don't have the time and patience to do so. If you'd like to read reviews of every shelter known to man and the pros and cons of them all, then read something like SectionHiker. I will say that if you think you can sleep and be comfortable in a hammock. Do it. Invest the time and research and talk to hammock campers and find out how they stay warm in different temperatures and dry in all weather. Hammockers have a distinct advantage on the AT because there are ALWAYS trees around you can hang from. I have a slight jealousy for people who hike with hammocks.
BearPaw Wilderness Designs Canopy Tarp. Eventually I put a Nettent 1 underneath it to gain a bathtub floor and bug protection.
Somewhere around New Jersey I switched to a TarpTent Contrail. I was swayed after spending yet another wet night at a less than ideal campsite. I wanted something lighter if possible, more internal living space and something easy to set up. A few of my hiking buddies all carried Contrails so I was familiar with the tent. I have to say that I LOVE this tent. I carried it all the way through Maine and will no doubt put many more miles on it in the future.
The tent has held up for me in fiercely windy nights, like the night in Monson when we camped in a baseball field despite warnings of 60mph winds that night. It was VERY windy that evening, can't say exactly how windy but the wind and rain was kept on the outside all night. I will say that the proper pitch does require a bit of practice to know exactly how all the walls and floor need to be setup. I love the ventilation on it, the large living space and the ease of setup. If you are comfortable with a tent that sets up with you trekking poles than look no further. Just remember to zip up your door on buggy nights.
Six Moon Designs Lunar Solo
The thing about them is they are first come, first serve. Often times they are full by the time you stop hiking, which in thru-hiker terms is just before sunset. A few caveats about shelters.
1) You are sleeping shoulder to shoulder with 4-12 other people. Every noise they make (SNORING, getting up to pee, making breakfast) can, and will interrupt your sleep. I grew to dislike shelters unless it was me and my hiking partners as the trail went on.
2) MICE!! Yes, the animals in the woods have learned that they can dine on your crumbs almost every night. The mice have been known to chew straight through packs and food bags to get at your next days food. I met a few people who woke up missing an entire days food (minus the Ramen, even wild animals don't eat that junk). And guess how they get to your food, by climbing over you and around your head. Mice are not the only ones in the forest who scavenge off of hiker scraps. I remember one day in Maine when after lunch I laid down for a quick catnap. I awoke to a feeling of a small animal running up my legs I had propped up on my pack. It startled me suddenly out of my sleep.I twitched my leg and saw a chipmunk that had been running up my shin flying through the air towards my face. It hit the shelter floor right next to me, jumped onto my buddies leg and leaped out of the shelter. It was hilarious but a deterrent in getting that 20 minute nap I like after lunch. Keep things like that in mind. I have many other animal invades shelter stories but that will do for now.
3) There are some amazingly nice shelters. Some so close to roads that you can order pizza. The other side of that coin are shelters that after sitting down with your Nutella wrap for lunch and propping up your feet, you realize that the entire roof is full of wasps (proceed to run out of shelter like an idiot). They will no doubt save you from a bad storm once or twice and subsequently, you will be banking on the fact that you can push on the extra 5 miles you didn't plan on doing to find the shelter full.
You can make up your own mind on how you feel about shelters. They could always be worse. If I could offer one bit of advice for anyone, it would be to try a few nights of cowboy camping. Sleep out in a field or on a rocky outcrop on a moonless, clear and starry night. You'll have to gauge humidity and dew points but the nights I remember best from the trail will be the good and bad nights that we threw our sleeping bags out under the stars and went to sleep. I would wake up on those nights and peer out of my bag and be amazed at how many stars I could see. Being deep in the mountains and high in elevation lessens light pollution and offers incredible views of the nights sky.