Hi Greg,
1. as Alan D mentioned
AirQuiz - Online Practice Examinations for Pilots! is worth it.
2. And definitely the Confuser.
3. Furthermore use 'flashcards' (there is a software called Mental Case that works on both computer and iphone/ipad. I made a lot of notes on it while studying and still review those in spare moments. Handy).
4. If the results of the group I was with can be of any help : those who studied with the Met book of Jeremy Pratt had the worst Met results, while those who studied with the Met book of Trevor Thom passed thumbs up. (the opposite was true for the other subjects).
In any case try to get the Confuser.