So, got my HydroBlu, and it seems pretty slick. I bought the full "package" with some bags and hoses and such. While its slick how those bags screw into the filter, I really don't see how you would fill them up in the field... other than from a spigot, which obviously isn't useful.
So here is what I set-up:
I got an old, grungy, 100oz hydration bladder (Deuter) and connected that as my dirty water bag, and a bit of hose to a quick-coupler that I've had sitting around that allows me to filter water directly into my hydration pack hose.
No doubt, this will need some refinement, but it seems like a good starting point. The whole set-up weighs 1/4lbs less than my old Pur hiker, packs a lot easier, will be faster, and less effort to filter, and if necessary gives me another 100oz of (dirty) water when its going to be a while between water sources.