M.U. falls into the classic example of a compilation that is bound to irritate the dedicated yet will satisfy the needs of less devoted listeners. Since Jethro Tull is a prog rock band that made cohesive concept albums, there will always be an audience that will believe it is impossible to assemble a coherent anthology, but the fact of the matter is, the group had a lot of songs that were staples on album rock radio and M.U. simply compiles those tracks for listeners who don't want to invest in a series of concept records. Besides, the resulting compilation is an entertaining listen, thanks to such genre classics as "Aqualung," "Thick as a Brick," "Bungle in the Jungle," "Locomotive Breath," "Living in the Past," and "A Passion Play." These are the songs that define Tull for both hardcore and casual fans, and that's the reason why M.U. remains a popular and useful compilation, even if it isn't definitive.
AllMusic Review by Stephen Thomas Erlewine