I use these lamps for 4 months, I heard that c'tait good copies of svetlana, would see its effective long-term but for now I am sure they reflect the character characteristics of the amp, then the 6L6 are much more powerful than the EL34.
inconvniant is that the only really hot, at least I know if it's a inconvniant because in winter, your amp can be used as radiator