I posted this on the LPF, thought maybe someone here would be interested...
I just picked one up when I was dropping my Tele off at my tech's... holy crap! I would have never thought it would have made such a difference. Increased sustain... more presence... a more "full" sound... the notes just pop. The only downside is having it clamped to my headstock. Kinda unsightly. It does help balance my bottom-heavy Les Paul a little. I think I'm gonna try to find an old Fathead, which bolts to the back of the headstock. My tech said Groove Tubes was going to start making them again, but she didn't know when.