I have always been a Borg fan. They are not intended to be the ne plus ultra of visual refractors. They are designed to be good ED doublets that offer the maximum aperture in the smallest and lightest possible packages. In addition to breaking down into multiple sections for easy transport, when assembled, their weight and lack of heavy triplet cells/large and heavy focusers at the end allow very light mounts and fast cool down time. As I said above, where else can you get a very good 5" ED refractor that weighs seven and a half pounds, comes apart and travels in a backpack, will mount on a cf tripod and costs about $4000 new? Dave