Jim Carrey is funny to watch, as always. Meryl Streep is also funny. Jennifer Coolidge is almost unrecognizable, and (as we see from the DVD extras) her funniest scene was cut. Also here are Jude Law (in narration and silhouette), Craig Ferguson, Jane Addams, Luiz Guzman, Catherine O'Hara, Cedric the Entertainer, and Dustin Hoffman (in an uncredited cameo, also with his funniest scenes deleted). And the look of the movie is interesting, the special effects are great.
But: I guess I don't really get the appeal of a PG-rated movie that deals in serial murder.