Reviewers have got to get rid of their 360 hard on

[Reasonable]

I don't think it's a huge problem.  Sure, particularly with US based sites/reviewers you can tell that, as the 360 is the more dominant platform in the region, their general bias leans to it, but for the most part it evens out I think.

Most decent sites seem to review/test both and in most cases seem to note any issues on either side - be it PS3 port issues a'la something like Bayonetta or 360 port issues a'la somthing like FFXIII.