Rating is all about gut feeling because believing in your gut is very manly.
Believe it or not, I used the full 1-10 scale. Nothing deserved a 1 because putting stuff out there by itself is a tremendous feat. 5 are stuff that's just very inoffensively mediocre but I don't feel like I wasted my precious time.
Anything below 5 are stuff that I really hate for some reason. Most of them are actually promising stuff that totally failed my expectation. It changes from time to time but right now I really hate Code Geass and the first Gundam.