For me, the only pedal that has ever qualified as "amp in a box" is the BJFE Honey Bee. Lots of great OD pedals out there but it's basically the engine of my board. It responds like an amp when pushed by other boosts and ODs. On it's own it's like a small combo cranked up. It's the one OD pedal that has remained in one form or another for the last 12 years of my playing. Great, great design.