I have the Lecture notes books and have used some of them. The Biochem/Genetics, Immunology section, and Anatomy book are all pretty good. The path book is pathetic, I don't like the Pharm, and the Behavioral science book personally but they are ok but I am not using them. I have seen the organ system books also and they seem to be the same thing but more condensed into smaller writing and pictures. Either way you can do well with either, but I am only using select ones. I am horribly disappointed with the majority of the Webprep lectures that correspond to the lecture notes books. I litened to all of them for the ones I used, but can't stand the lecturers for Phys, path, pharm, and immuno.