Sat for level 3 for the first time yesterday, here are my thoughts:

AM: very reasonable, I think I did okay, the mistakes that I probably made were more due to lack of preparation than hard questions. Hard to say for sure how I did.

PM: some very specific and obscure questions, including some on topics I didn’t even remember seeing in the books, much less remember the specifics of! However I felt the questions themselves were usually straightforward. Just make sure you got the basics down for everything in the books.

I felt (like some others here) that because of the shorter format there are “not enough” questions, in the sense that the format inevitably focuses on some specific topics, and so it comes down more to what you revised the day before and still have fresh in your mind. Pros and cons, I guess.

Feel free to AMA about the Prometric aspect.