I figure your talking about the PPL books? I actually prefered the AFE ones when doing my PPL....I felt their diagrams and the way they worded the material was better suited to my learning style.
The material isn't hard for the PPL, nor is it complicated to learn, most of it is quite easy! You obviously haven't seen the amount of pages in the ATPL books then? and guess what...theres 14 of them!
The quicker your heads are in the books the faster you can get the exams done! Its a good learning curve and some of the material can be quite interesting.