I read somewhere that the simplified OBIGGS used for the 747 test weighed in at about 100 pounds, and would be lighter for smaller aircraft. That's not bad.
The only real issue I see from the flight tests, is a noted degradation in the performance of the ASMs (Air Separation Modules - contained the hollow fiber membranes) that accumulates with usage time. The cause is not know yet, and could effect the long term performance of these systems. It is known that hydrocarbons and HFMs don't react well together, and particulate matter tends to clog the HFM, so maybe these are the causes.