Which brand do you think made or currently makes the best metal halide lamps? Is it EYE, Sylvania, GE, Philips, Plusrite, Westinghouse, Satco/Hygrade, or Feit Electric?

I would say EYE. Ushio did also make a decent lamp, but they were phased out within the past few years. The big names are putting out some very questionable quality legacy lamps right now.

Philips, Osram-Sylvania, BLV, GE-Tungsram, Iwasaki, Ushio, Venture, Welch-Allyn - all of them did some great MH lamps at some time. Even Chinese Yaming and Yamao also made some interesting unusual lamps too!

Overall, I'd say Philips was the most innovative. Blowing all of their competition out of water with new ceramic MH series in early 1990's. Light quality was just unbelievable at that time! Still remember getting my first /942 Philips lamps, and these 30 years old lamps are remaining to be competitive even with LEDs of today...