is n't as compelling or as believable 
(ROOT (S (VP (VBZ is) (RB n't) (ADJP (ADJP (RB as) (JJ compelling)) (CC or) (PP (IN as) (ADJP (JJ believable)))))))
(ROOT (S (VP (VBZ ) (RB ) (ADJP (ADJP (RB ) (JJ )) (CC ) (PP (IN ) (ADJP (JJ )))))))