Silent Hill 2 is just about as good as anyone who played it will tell you it is, but I also think that it's internet discussions - and discussions about the Silent Hill franchise in general - are a bit misguided and shallow. This is a very intorspective game by nature, it is impossible to talk about it and add anything substantial without leaving yourself a bit vulnerable. However, I myself am a bit of an hypocrite coward, so I'll take about things I really find compelling about this game without any spoilers.
I really love how the game leaves so many things up to interpretation about what trully happened in the story, trully a mysterious game by it's nature. Not only because you need to interpret the events from the game, but concepts, locals, characters' actions and such.
The supporting cast does a fenomenal job at helping this "mystery" about psyche grow in a constantly interesting way, even if they are lacking many times. Their actions and REactions are really important and add a lot to the story. That's what many people tell, but I really like to think about what it means for them to be there. I personally believe that those characters aren't just there to add substance, but also to guide you to unravel more behind James Sunderland's struggles and thoughts. I like the idea that maybe even more than characters, these people are ideas that are molded by the protagonist.
I also think that your reading of the story may vary depending on your own living. Maybe you won't understand a certain character's choice or action, but I think that even this misunderstanding makes the game more eary and interesting. It doens't try to spook you, generally speaking, it seems more interested in disturbing you through it's content and implications. The scariest thing in the game to me was something that many players might not even see in their first playthrough.
I don't really know how to write a conclusion to all of this, I'm not a professional... uh...
Please play the Silent Hill games