Dunno, on one hand, they both have terribly written characters, with the exception of the lead, returning to an island (or, in Grant's case, another island with the same premise), the characters are complete and total morons, plot holes aplenty....but on the other hand, JP3 didn't completely ruin a great book in favor of Vince Vaughn basically screwing over every character....but TLW also had a theme, whereas JP3 was a monster movie...which is against the whole point of the first two...but the finale isn't as stupid and disappointing as TLW...
Jesus, let's just say JP is amazing and the other two are both as good/bad/mediocre/what have you as the other.