Comments about Outdoor Research Highland Bivy:

I have used this Bivy on the Big Bend Outer Loop trail (30mi). As I needed to pack all the water I could carry for this desert loop the Bivy was a perfect alternative to a full blown tent while providing protection from things that scurry around in the desert night. It is Waterproof (heavy floor) and still provided good ventilation - I did not have any moisture build-up etc, It did feel a little constrictive at first - but I was soon comfortable with it. straps inside to hold a pad in place, and enough room to hold my clothes and boots inside with me. The single arch pole helps a lot keeping it off your face/chest and I liked the ability to open the flap with the netting in place to star-gaze bug free.
This is a great emergency item too for Day Hikers and even search and Rescue work - compressing down realy small and light - you won't get caught out without a roof over your head in the event your trip plan is changed without your permission. YEA space blankets or a plastic sheet are lighter -- BUT this is warm, dry, and bug free. You'll feel really really smart when you have to whip it out.