dougstubes.com is good. That's where I got mine. He burns them in so there is less chance of premature failure; a nice service not all vendors offer. $15 for Tung Sols plus $6.65 for shipping and insurance.
I have a JJ on my AVT combo and it sounds good, the clean channel is more responsive when using my multieffect, and the OD channels is more responsive now to the volume on my guitar
Prior to the JJ i had a EH, sounded good at lower volumes but a bit muddy compared to the JJ, however at lower volumes i like the lower end response of the EH better but loose some of the brightness