I've been looking at tarp shelters to include in my BOB, and now I'm wondering why I would want to go that route rather than an inexpensive two man tent like the REI Trail Dome ($99). Reasonably sized tarps of decent quality (not the blue tarps from hardware stores) are not cheap. Even if you go for the lower-end ones. Other than maybe 2 or so pounds of weight savings, I can't find much reason to justify a tarp setup for BOB use. A tarp would give less protection and present a more complex setup most of the time. And dealing with shifting wind patterns with a tarp could be tricky. I fully understand why someone would choose a tarp just for the weight savings aspect. But are there other reasons? I'm thinking, just buy the REI 4-1/2lb tent and be done with it.