My bags arrived today from Epic Designs (thanks Eric!). Beyond being just sexy, they add a lot of room to the rig with very little weight. I thought the box was empty when I picked it up off my porch. Seriously. The technical attention to detail is beautiful as well. With as light as they are you'd think there wasn't anything inside. The frame bag has a lot of thought put into it with a drop away compartment separator and mesh pockets to keep gear organized. The seat bag though is a real work of art. It has a tons of room, is still light, and has been epically designed so that the straps are doing double duty as both compression and support. It's one of those awesome things that makes you wish you had thought of it.
Disclosure: I don't have a special relationship with Epic Designs. All products have been purchased from them through normal channels.