The English prep course is more focused on grammar and the specific themes required in the matriculation exam. The Comprehensive British English and Comprehensive American English packages have more vocabulary related to certain other themes, such as travel and business.
Another difference is that the Comprehensive course packages can be used even by complete beginners, while the prep course requires at least intermediate language skills.
When comparing prices, please note that the price of the prep course includes a grade guarantee.
In short, if you are going to participate in the English matriculation exam, we recommend the prep course. If you want to improve your English skills for another reason, such as travel or work, we recommend choosing Comprehensive British English or Comprehensive American English.