The first part is the best - a beat-for-beat parallel of the first book. Then it starts to deviate and gets kind of self-absorbed.
The author, Eliezer Yudkowsky is a famous AI researcher with somewhat controversial opinions. You may have heard of his piece “If Anyone Builds It, Everyone Dies”.
He’s also witten “Rationality: From AI to Zombies” which might be interesting if you like the “rationality” aspect of the fanfic. It’s really dense, though - I’d very much recommend anyone to start with HPMoR.
Wow, no AI. It would be a pleasure to have such stupid device.