I rather enjoy the rating system developed by the crew at Double Toasted. In descending order, each with a "high or low" option:

Better than Sex: This film is excellent, and pushes the boundaries of cinema as an art form.

Full Price: A very enjoyable film which is worth paying full price for in the cinema.

Matinee: Worth seeing in the cinema, but not worth paying full price for, or at least during the initial theatrical run.

Rental: Can be enjoyed, but still has a variety of flaws. This is worth waiting paying very little to see after the theatrical release.

Some Ol' Bullshit: The crew recommend against paying any money to see this film, and has very little that redeems it.

Fuck You: The crew actively recommends against seeing this film at all. This rating is typically given when a critic is angered or offended by a film's content, and indicates that it has absolutely no redeeming qualities.