Where can I find ratings of anime OPs and EDs?
Gendou's Anime Music has ratings on the opening and ending songs and offers links to buy the songs. 

You commented that you are looking for something for something rating the animation as well as the music, and I don't know of anything like that, but Gendou's Anime Music site is a good reference for finding opening music based on anime title and for rating the songs themselves, so I figured it was worth a mention at least.