I like the WE ones. They were moving recently and setting up a new production line somewhere down south, so supply of them is hard to find at the moment - maybe sold out temporarily. They set the standard in this tube and have been doing so for 60+ years.
40,000 hours is fairly unrealistically optimistic. A lot depends on the amp, but even driven at low power, it's not likely to get 40,000 hours out of a set, despite the 'myth' about that. Guaranteed they will be pretty spent even @ half that usage. Tubes just dont' last that long, esp. power tubes. (think: that's 8 hours a day for 13-14 years straight. No....just not realistic)
They made the 'old' version up until 1989, then stopped, thinking there was no more market. They brought the line back up some years later, in the 90s... I don't think it took them 5 years just to restart the line (though they are notoriously slow, re: product developement) - most of the tooling and some of the workers are originals from the old production. There's tons of good info on this @ their site, www.westernelectric.com
-Ed
