I'm looking to simplify my shelter system and move away from tents. I usually hike with my dog, so I'd like to stay away from going tarp-only and was turned to two-person bivys (bivies?) Anyway, I found this one from Exped:
http://www.exped.com/exped/web/exped_homepage.nsf/0/02A8941FB846F967C1256F2B002F6A43?opendocument
Does any one have any experience with this or something similar? Exped says it's waterproof, but would I still need to bring a tarp to cover it for rain? Will condensation be a big issue in AZ? The idea of getting a light-weight bivy for two that doesn't need a tarp and could function as my rain jacket as well is very appealing, especially at its price.
Oware also sells some two-person bivies (http://shop.bivysack.com/category.sc?categoryId=2), but they are more expensive and sometimes heavier than the Exped BivyBag Duo and most seem to require at least a tarp to cover the mesh over the face. Am I missing something here?

