I got one and it just hasn't stuck with me. I've pulled it out a few times and every time it ends up back on my shelf. The distortion sound just wasn't for me. It's very tweakable though, so I'm gonna mess around with it a little bit more, but I have a feeling I'll end up selling it.
I'm on the fence about this one too- it's so versatile that I want to love it, but the first time I tried one it didn't work out. The boost / OD side can be a bit splatty, and the disto side can be a bit grainy, but then I suppose versatility includes sounds I don't like as well as sounds I do. I never tried it at 18v.
Still, the mid control on the disto side works great, and the highs control on the boost side seemed to accentuate the highs (odd, since i thought it was a passive tone stack), which can be very useful for getting a bit of sparkle out of darker amps. Enough gain for metal, at least anything short of the cookie-monster stuff, though it won't transform a drri into a stack. "Feels" like an amp. Well built like all the Fulltone stuff.
So, to sum, there are great sounds inside the gt500, but the tonal range is fairly wide, so it isn't just plug / play. All in all I give it a
I just got one. I agree with what's been said. There are a ton of tones across the two sides of the pedal, separately and together. The distortion side has a certain characteristic to the distortion sound that is what I'm coming to think of as "the JFET sound", based on a few pedals I've heard that are advertised as using cascaded JFETs rather than op-amps/diodes for clipping.
It's a deep pedal, and will take considerable tweaking to really get it. It isn't dropping my jaw so far, but it's pretty cool.