I took NS 5 back in summer 2015. The aamc scored exam wasn't even out then, so I am not sure how it could be similar to it beyond having the same look, tone and format of the exam. All of the NS exams do a good job mimicking the aam style tone and format pretty well. As far as content, most of the NS passages I saw were based on science articles or discussios of a study or scientific concept. There will likley be some topics that you see more than once if you get to 5+ full lengths, just like the aamc has repeat passage ideas, just different passages testing the same science. I don't think any one test can spoil your AAMC practice or scored exam.
NS updated all of their exams for 2016 and they now have 10 full lengths. I have not taken 6-10 but from what I read they are better than they were before, and back in 2015 EK and NS had by far the best practice tests already.
Anyone who has taken the new NS 6-10 care to chime in?
