I tried RD in local music store once and at that moment I knew I'd get it. I had to trade my Shiva for that and I kinda miss it but RD just blew my mind.
In this box you have an overdrive, a synth that can sound in unison or octave down from what you're playing and random noises. With synth and drive together you can get some very unique tones although you don't have any other controls but volume for each of them. And with octave down it becomes something like MXR Blue Box and steroids.
I didn't see RD much on other boards and I think this pedal is very underrated. And I also couldn't find a demo with bass so here it is, enjoy:
Dwarfcraft Robot Devil with IE Xerograph and Malekko 616 - YouTube