They had John McLaughlin on guitar and were awesome. Got a copy of one of their albums (on tape no less) from the drummer in a band I played with in highschool (who formed, rehearsed for 2 weeks, for the sole purpose of playing one show). He was also our school's computer teacher.
However, I dunno about "best" because, well, there's the Dixie Dregs. Mahavishnu is up there though. But maybe I just haven't heard enough MO.