Here's another Happy Camper video - this one is on the advantages of using a bivy and how to set one up. Bivy's are definitely liked or disliked by campers. It took me a while to get used to sleeping in one - and when I do, I always place a quality tarp over me.

What it comes down to, if you're looking for a very light weight sleeping quarters, especially for backpacking, or you just want to pack a light weight system as a back-up in case your tent-mate snores all night - the bivy is perfect.