On a side note, comfort is a relative thing. It's important to keep in mind that whether you pick a tent or a tarp, it's only part of a bigger system. How comfortable you'll sleep during the night depends on a few other factors, especially your sleeping pad and ground insulation.

One reason why I like my poncho lean-to setup is that it allows me to pile up lots of insulation underneath, which makes sleeping a lot more comfortable. Usually small spruce branches arranged like roof tiles about a foot high or a similar thickness of dry leaves covered with a thick layer of moss. On top of it a closed-cell foam pad and my sleeping bag. IME, that setup beats a tent and a plain sleeping pad any time in terms of comfort. It takes me about 30 minutes to make that kind of shelter with a knife or axe. Not much longer than it takes to set up a tent.

I've slept a good many nights under a poncho, anywhere from the mountains to the seaside (even in a swampy valley in the middle of the Scottish highlands once lol), in heavy rain and at temperatures down to freezing. It did get cold in my sleeping bag on a few occasions, though never unbearably so, and not once did my lean-to leak in the rain. So it's definitely a feasible alternative in the bush though it's not for everyone.