I enjoy cowboy camping, but I don't enjoy mosquitoes. I recently took my Bristlecone Bivy backpacking in Colorado for three nights, all above 12,000' and near streams/lakes. I have several small tents available to me as well as an older, heavier bivy, but was looking for something that gave me more of the feel of cowboy camping. I combined my Bristlecone Bivy with a rain cape/tent shelter so that I would have rain protection if needed. The bivy plus the tent shelter weigh about as much as my lighter, one-person tent (~16 oz), so no weight tradeoff for me, plus added utility (cowboy camping and a shelter that doubles as a rain poncho).
On the first afternoon/night, I set up the bivy under the shelter so that I could have some sun protection in the afternoon while I read a book on my phone. I thought about pulling the shelter down, but left it pretty open - good thing because I didn't expect it to start raining at 5:00 am!
I started with the same setup the second afternoon/evening, mostly for some shade so I could relax and read. When I wanted to sleep, though, the wind was blowing strong and the shelter was noisily flapping so I knocked it down, but kept it available. In the morning when I awoke, there was frost on all of my gear, including the bivy. The frost caused some condensation to form on the interior of the bivy - no big deal.
On my third day, I arrived to camp later than the previous two days, and had less time to lounge about and less need for sun shade. I only used my new bivy and kept the shelter handy. Before setting up the bivy, I made certain to air/dry it out, along with my quilt. I had a great night that night and no condensation.
Overall, I'm very pleased with my Bristlecone Bivy. I like that I can easily look up at night and see the bright stars. I like that it gives me plenty of room to roll around and bring some of my small gear into the bivy with me. I like that I don't have to worry about biting insects. I like that I can easily lay on top of the bivy exterior and not take off my hiking shoes and not worry about getting my quilt dirty. I'm a very happy camper!