Hi NilsB359,
There are some differences between the 5th and 6th Editions. Here's a brief rundown, but expect a more in-depth analysis via a Blog post (
https://www.manhattanprep.com/gmat/blog/) in the next couple weeks:
5 Quant Strategy GuidesEvery quant guide has between 1 and 4 new chapters containing all sorts of great solving strategies that used to be taught only in class or weren’t taught very heavily in the books. A sampling: Smart Numbers, Testing Cases, Working Backwards, Draw It Out, Estimation.
Sentence CorrectionWe’ve got a new SC Process that will help people get through these problems effectively and efficiently. We’ve also got a new chapter on Sentence Structure and much-expanded material on Meaning in SC—the two topics that have greatly increased in frequency on the GMAT in the past couple of years.
Reading ComprehensionThis book has gotten almost a complete overhaul, with all new strategies for reading passages, answering questions, and avoiding trap answers.
Critical ReasoningThis book hasn’t changed as much as the others. We have incorporated the “Fill in the Blank” question format into the main strategy chapters.
IR / EssayThe IR chapters received a huge overhaul! We’ve got new problem-solving strategies, new example problems, and new timing strategies.
RoadmapRoadmap has been updated to include all of the latest and greatest study and timing strategies that have been developed in the past couple of years.
I think if you're leaning more towards a January test date, you're already running behind and should begin studying as soon as possible with the 5th Editions - which are still relevant - but if you're thinking of pushing the exam further into March, then you should wait for the 6th Editions.
Because the OG 13 and OG 2015 are physically the exact same, the OG references in the strategy guides will remain the same.
Best,
Shan
Student Services