MIKA-the-better-one
I justordered some el84s I went with some Tung Sol's..... GT's are cool but they vary far to much for me to invest in them....
JJ's are the standard for me..... EHX do the whole SOvtek thing the best (can get a bit raspy at times)
Tung sols are my favourite so far....
OR some Mullards... but again a bit iffy
makepeace
GT's are rebranded everythings. As are Ruby Tubes, Fender (who owns GT), Peavey, TAD too I think and also tons of other "makes". They buy and own caches of old (and new) tubes that are sorted and tested for quality and performance (and then sometimes treated, cryogenics etc) and then classified. A respectable service to owners of amps I say, they're not a rip off as they have to front the capital to buy tons of tubes that may or may not yield a sale-able product and then all of the testing equipment, and in the case of treating - more expensive equipment, but they do not make any tubes themselves..
Companies that make tubes these days are few and far between.. New sensor owns most of the modern tubes brands (Sovtek, EH, Svetlana, Mullard, Tung sol etc), JJ-Tesla and the chinese companies (Shuguang etc) are other examples. Some of them have some great offerings at competitive prices for your everyday tubes (esp for guitar amps where imperfection is sometimes preferred).