Good point Judge. The reason I think Leventhal was probably more influential in Guest's work was because there are a number of scenes in A Mighty Wind that have counterparts in Wasn't That A Time - the Weaver's getting together at a picnic, the rehearsals, the concerts,etc.   Guest apparently did his homework, and while he created fictional characters that are completely different from Leventhal, Weavers, etc., you can see where a "novice" could draw comparisions. (I also found a scene in A Mighty Wind that reminded me of Ballad of Ramblin Jack - the characters were driving around trying to find a hotel was similar in style to the scene of Elliot trying to find his old home.) That is the point that the NYTimes review made - Brown was able (for the most part) to avoid the comparisons.