Manhattan GMAT 4th Edition vs 5th Edition

Thanks bb for your effort.

I have carefully read through both editions of the SC book and it's not difficult to notice a slew of changes. To name a few (not a comprehensive list but just what pops out of my head):
1. Chapter 2: de-emphasize CONCISION (with a discussion on the weight of CONCISION, showing that it's just a "preference")
2. Pronoun: de-emphasize PRONOUN AMBIGUITY. This section changes a lot, even with a sentence previously considered "suspect" but now considered "correct". Delete some previous "rules" (including the notion of "too close").
3. Chapters on MODIFIERS and VERB FORMS: I notice some minor changes that better clarify the concepts or better explain the sample sentences.
4. Miscellaneous issues that I can think of: no longer treat "such as vs. like" as a hardline rule, in light of official publications.

In summary, I would say the SC book has considerable level of changes that conform to the trend of the test.

For the RC book, I think the changes are almost unnoticeable. (I acknowledge that I did not read word-by-word for both editions of the RC book as I did for the SC)