Picked this up on the cheap...allegedly models a Distortion+, a DS-1, and a Rat. Conveniently, I happen to have those handy. Looks like a fun weekend project!
It's ok. I have always found it to be a little fizzy for my tastes. Never was a fan or connoisseur of them, just not my sound. I have it mostly for "it's a classic" purposes and it is more than good enough for me for that. Might get a little Randy on with it every now and again.
Yeah, when my original finally died, I got the Yellow with the LED and lasted a day with it. They are just way fizzer than the mustard block letter units. And if I remember right, the treble was more intense. The treble on a D+ increases as you increase the gain, which works for me seeing home much treble I dial out of my amp. I bit the bullet and bought an 80's unit I think it was only $50 more or so.