Nothing to worry about in a sense. Leaks, etc. are going to become common with big titles, particularly when they are seen as flagship titles.
Also, given we've had a few early good reviews and an early bad review there is no evidence of any manipulation I can see. PS3 mags get first dibs often - funnily enough so do 360 mags.
As the videogame industry continues to grow you'll also see more opinions popping up in more funny places - I mean Maxim! But that's just like you can look to very established film review sources, or pickup a TV listings magazine and find they've thrown in a few words on The Reader.
It just means those who are interested in reviews are going to have to get used to considering the source, getting a feel for its understanding of games, objectivity, etc. and apply that to how they consider the review.
For films there are reviews I read where I adjust down, up or ignore simply because I know the source and how my own views/preferences stack up vs it.