Joe... I was surprised at the tin foil hats remark from Rob, but I do feel he was jumped on just for providing good solid educational information and responded in frustration. Rob is not presenting his opinion on things other than to say if you are providing conservation framing you should use a glazing that meets the accepted standards. If you choose not to accept those standards then so be it, but realize that you are not offering the highest degree of preservation framing. I'll say again that you should first inform yourself so that you can provide an informed recommendation to your customer for whatever work they bring in. I sell a lot of Tru-Vue Ultravue glass which only has about 65% UV protection to customers that don't care about preservation as much as presentation. I sell CC glass to people who are on a budget but prefer a high degree of preservation. I sell Museum glass to those who want the best of both worlds. I don't have ArtGlass available to me or I would probably consider offering it too if the price point was significantly better than MG or the difference in clarity was that much better but I would also let the customer know that it is not up to accepted conservation museum standards.