Boss DD-20 = oh god complicated. I've played with it in the store and I am not sure why you'd drop that much dough on a pedal this huge and complex instead of just saving the money towards a serious digital multifx. It sounds like a Boss digital delay, which there's definitely a time and a place for.
I dunno, just seems to me that there's limits to the interface you can put on a pedal before you defeat the purpose of having the effect as a pedal, as opposed to a rackmount. The DD20's awfully close to that.