I really like the OR Bivy. Mine is about 12 years old and it still wear like new. I mainly use it for fast overnight hikes. I was using it when I hunted, but my Hennessey Hammock has filled that role.

The problem with a bivy is when you face the possibility of getting stuck in one for several days because of nasty weather. On the other hand it packs up small, it's light, and it's pretty comfortable if you're not spending any great length of time in it.