I have a friend who is making bivvy sacks out of Epic. He made me one that is modeled after the Bibler bipod bivy--sort of a one-man tent that weighs in at a scant 1 lb 7 ozs including the pole and stakes. Crams up about the size of a large pair of socks. (If anyone wants to order a custom-made bivvy out of epic let me know).
I set it up and hosed it down in my back yard for about 5 minutes or so. Water beaded and rolled off the fabric no problem. The interior was dry as a bone.
Oh, and I had not seam sealed it.
Epic is the shit for lightweight personal shelters that I have tested. I imagine using it fora tent would be just fine with one caveat: the fabric is very thin and therefore pretty fragile.