Self studied PPL using ATC with average results, did a course for CPL with excellent results, self studied IREX with a perfect score, self studied ATPL (using the recommended readings from the syllabus, not a course), again with average results. Of course that was all many years ago!
Either way is fine so long as you are learning the required knowledge, if there's something you are stuck on I'm sure your instructor/CFI will help out.