Mr Duncan's stories about what he did for EVH have changed over the years, and he's been sued or warned numerous times to stop selling "signature" pickups. He was also accused of stealing other peoples' designs in years past.
I saw QOTSA at Lollopalooza around 2002. Didn't know who they were, didn't impress me at all. Pretty boring. Audioslave and Jane's Addiction tore it up, though.
The change was around 1995. The original UL had 2 pi tubes. Around '95 they changed to 1 pi tube for a year. The next year they went back to 2 pi tubes, and the design stayed the same until now.
Oh, it's great there for lead playing. Very balanced for high gain. Not too bright or too dark. I had one in my PRS for awhile, eventually went for a 36th because I wanted something more vintage. It was great for modern leads though, wouldn't hesitate to use it again.