Instruct: Classify the given review as either positive or negative.
Query: Up Front and Pure Be-Bop

Mario approaches composition as an engineer, so his music is more engineered than composed. He is the most hard-working bassist that I have ever seen. He may consider himself avant-garde, but hey all be-bop is avant garde and anyway, his stuff is always original has a broad variety, played in many key changes and just great jazz. At the same time, he is cutting edge and masterful in composition, theory and technique, all his albums are just terrific; my favorite is "Boom".