Why does halo 3 have higher ratings than killzone 2?

[Skeeuk]

WheelStriker said:

Killzone 2 is no doubt an AAA title and a must have for all (new) playstation 3 owners. But it's no better than halo 3. Because halo 3 has higher ratings (and more sales).

Can someone please explain why this is?

And please no comments like "because killzone 2 sucks" or "because halo 3 is more fun and  BETTER than killzone 2". These kinds of comments will be ignored.

its because halo is a ten times bigger ip than killzone. no matter how good killzone is it will never match halo sales popularity.

regarding actual game in hand, halo is a fan favourite, and is massivly overhyped, therefore reviews will just give it 10`s across the board. although it is a very good game.