I think an 8/10 from EDGE is a good review. They place good games at 5, and work up or down based on expectations. MK Wii got a 6, AC got a 7.
They say in the final paragraph about MGS4:
"But it is faithful to its fans, its premise and its heart, delivering an experience that is, in so many ways, without equal"
Sounds good to me :)