Can't speak for the other choices you mention, but I own a Ti Goat Ptar and love it. I was out in some steady rain last month, and once a few weeks ago with some light snow, and was glad to have it because of wind and dripping from my tarp (I would say half of it is condensation), especially with a down bag. When I woke up in the morning I watched as several drops of water bead away from on top of me as I got up, dry as a bone. I was also surprised at the temperature bump it gave me, but I should note that I seem to have a higher tolerance for cold than some people, so little bumps of warmth I noticed more perhaps.
The bug net is nice too. We get lots of bugs here in Sweden, so that was important to me. If I have to be knit picky, I guess two things that I could give criticism to are the zippers and the entrance. The zippers are small and tricky to open, especially with gloves, and it if you have to pee in the middle of the night, it sucks getting in and out. But the zippers are honestly not a big deal, and pretty much all bivy sacks are tricky to get in and out of from what I have gathered.
I like that there are loops on both the hood and bug net, so if I want I can tie them to something for a dome effect, but so far I have only slept with it with it open (no bugs around in winter).
I should note that I am about 6 foot tall and 180lbs and the reg size fits me just fine, along with my down bag and reg size self-inflating mat.
Hope this helps.