The Confuser seems to be considered as essential, but I got through all exams with a good result using the AFE books only.
I where about to buy the confuser but didn't do it in time for my first exam (airlaw) and had to rely on the "Private Pilot's Licence Course PPL Question & Answer Simplifier" by AFE. This went well so I decided not to buy the Confuser and used this book for all other tests as well. It has 3 mock tests for each subject and a really useful "essential review" for each subject. It has explanations to why a certain answer is correct using crossreferences to the other books in the series.
Private Pilot's Licence Course PPL Question & Answer Simplifier : AFE