Harry Potter, Scientist edition. I liked all the starting stuff which is basically Harry pointing at the whole Rowlingverse and saying "this is stupid and shouldn't work". And it ends well; all plot threads pulled together, satisfyingly and interestingly. It palls rather a lot in the middle; I felt a bit guilty about having so enthusiastically recommended it to friends when I got bored with the middle bit, but the end redeems it, mostly. No desire whatsoever to go read Yudkowsky's rationalist writings, so if this is secretly a first-hit-is-free seduction attempt then it didn't do a very good job.