I've been lucky enough to have had the ID4 since Jeff started working on the prototype after we discussed how great it would be to have a dedicated stereo instrument to line level driver so we could send keys and bass and guitars direct to pro tools without having to use a mic pre. The speed that this device allows is astounding, but the saturation circuit is why this unit is so amazing. When engaged it imparts the phatness and depth of a mini moog to any keboard or bass you run through it. It's the kind of effect that makes something jump out in a mix. It's the magic that you hope for after hours of tweaking and it is all in the touch of a button and a knob that when you turn it to the right makes it awesome. I have the decapitator and it is great at what it does. The ID4 is something different. It doesn't just tear stuff up or make it sound like a distorted boombox (which I love) it makes things huge first and then you can add distortion and crunch to taste. It's the depth and phatness that makes the ID4 truly unique.
I have been using it lately on an NS-10 speaker in front of the kick drum with saturation in at about noon and going directly into pro tools. It's the greatest "fits right in the mix fat and tight sub" I've ever heard.