I think you guys are confusing the hardware BBE maximizer (mentioned in GlennT's posts) and the plug-in software version of the BBE that works with things like Sonar and Sound Forge (metioned in freddynl's post). I use the software plug-in BBE for my recordings and it does reduce the muddy mids and adds crispness to the highs. On stage with my full PA rig I use the Behringer Ultrafex
Pro 3200, which is a combination sonic maximizer/bass enhauncer/stereo seperation enhauncer:
http://www.behringer.com/02_products/prodindex.cfm?id=EX3200&lang=eng