Rating: 5 / 5
The Soul Bivy has undergone continual evolution and the new versions favor the lighter, more breathable but less water resistant (than Epic) Momentum fabric top. My MLD Soul Bivy reflected some of this evolution, notably by the incorporation of a larger surface area of breathable fabric being used in the top and hood, compared to many competitors, as well as a more generously sized hood.
My Epic fabric Soul Bivy weighs in at 8.5 oz. in a long size inc. the zip in mosquito mesh and Ti wire hood hoop. It has been a constant companion on SUL forays in the Cascades and the Sierra and a sleeping bag cover in the Winter in both tents and snowcaves. The bivy is sized generously enough for at least a lighter Winter weight bag (optional Wide version would hold even loftier bags. The "stock" Soul Bivy w/ Momentum top weighs in at 6.7 oz.
Among unique features are the drawstring bottom which is useful for venting ( helps keep the feet of the sleeping bag more condensation free) and temp. control on warmer Summer nights. It has stake out corners and a hang loop to hold the hood from the face as well as a removeable Titanium wire hoop (highly foldable) to hold the hood away w/o relying on a handy tree branch. Like most bivvies in the UL class, it has a across the chest zipper ( a Side Zip model is also offered).
The MLD build quality is impeccable and many options are available ( including Epic and eVENT fabrics)---essentially making each Bivy a custom affair.
note: the 2007 model has an eVENT foot section to improve breathability in the foot section w/o the sil nylon bottom wrapping around the feet ( a condensation issue).