IMO, the silvered glass reflectors ALWAYS out-shone the polished metal reflectors with operators who cared, giving them a quick wipe with virtually EVERY trim change coupled with a thorough cleaning monthly. Anytime a performance was to be nationally televised, the network LD's would have us optimize all four then lay full body shots in order across the asbestos (Yes, REAL asbestos) then measure both the direct beams as well as their reflected intensities off the asbestos. Time and time again, the carbon supers left the 1K6 xenons in the dust. We normally kept 1, new in box, spare silvered glass reflector in stock and a pair of used, but well cared for, polished metal reflectors just in case a 'ham-handed' visiting op' had the misfortune to drop a glass reflector but, I can't recall ever doing any seriously measured comparisons of the metal vs. the glass. Toodleoo! Ron Hebbard.