I think the main reason Silent Hill looks a lot better to me is because Silent Hill leans more towards horror and not action. I don't know if you've played any of the Resident Evil games, but for me the whole series went downhill after 4 because of the change of style. Resident Evil used to be a survival horror game with clanky tank controls but now it's pretty much a 3rd person shooter with puzzles.

Anything Resident Evil related that has action in it makes me want to fuck a cat raw.