I heard those trembuckers sustain for days and adds any sustain that is lost in the tremolo. I guess that's supposed to have the depth of a hard tail setup, yet allow for the trem action, too. I would like a trembucker for Gibson spaced guitars such as a Gibson with a Bigsby. That could open up a ton of possibilities.
the parallel axis trembuckers in my guitar is great.
I have the distortion model for bridge, it screams, punchy, warm as well, and the brightness/ treble is just at a maxium limit I can take, if they make the treble 1 level higher, I'd be hating it.
the neck is the original parallel axis neck model, it's sound and act pretty much with single coil edgyness, very bright, be very careful with this one.
you put your amp treble too high, the treble will kill you.
regarding the sustain... hm.. I think it's normal, it's nothing like sustain for days.
but just at right amount.