Hmm, I tried the MXR BD in a store yesterday and was less than impressed. Played with two passive basses. Tried many different settings, but it always sounded "farty" to me and the guy in the store. It looks like too much of the low end is passing through the distortion circuit, especially in LED mode. Reminds me of a RAT with Ruetz mod.
After all the nice reviews here, I really wanted to like and get the pedal, but at the end I couldn't. Matter of taste I suppose. Blending clean and dirty paths separately works nice though.