i used to own one...it sounded good, but it DOES suck out some noticeable bass...while i owned it, i used it in front of my emma discumbobulator in a loop w/ clean blend...i have since gotten rid of it as i have stripped my rig down...it was a pretty awesome sound in that situation, and it was great without the filter, but it still needed some clean bass under it to make it sound best
theres also a keeley mod to the blues driver to make it enhanced for bass, and the soundclips he had sounded very natural and smooth...check that out if u get a chance