I haven't heard the BAT so can't make an experienced comparison, but can tell you that the MP-1 is a genuinely world-class preamp and that in my expereince there is a wonderful synergy between Atma-Sphere amps & preamps. Every time I've tried Atma-Sphere gear with roughly competitively priced other (high quality) equipment and compared it with an Atma-Sphere-only system, I've preferred the Atma-Sphere-only system. That's not to say there can't be exceptions, but moreso than other equipment I deal in I've found staying in the family to be worthwhile with Atma-Sphere.
