Thinking of picking up a bivy to pack along on some of my hunts. My reasoning is that it would be a nice thing to pack along as I sometimes can get a ways from my base camp while pursueing game. Previously I've packed a sleeping bag and painter's drop cloth to keep me warm and dry if I had to spend the night out. The plan was to fold it in half and weight the corners down with rocks, but a bivy seems like a much simpler solution.
Here's the model I was looking at http://www.rei.com/product/747832. Does having the model with the hoop help ventelation enough to justify the extra weight and bulk?