Sofferman, a New England Conservatory professor who calls his group The Sofferman Perspective, has quietly become one of Boston's most interesting musicians and band leaders. As a drummer, he is nonpareil; he elicits a symphony of percussive sounds from his kit. As a composer, he is impressive; his tunes incorporate intricate melodies and utilize odd time signatures. As an improviser, he is remarkable; he shifts rhythms and tempos effortlessly and unnoticeably.   ~The Boston Globe