first of all, I am not biased because I haven't played either yet (my primary gaming PC needs to be replaced)..
and yes, reviews are always biased because they are based off of the individual opinion and emotional state of the writer, as such they are based entirely off the writers personal preference, thats bias.. only way we will ever see a non-biased review is if we somehow write a computer program to anolyze the product and output a review, because thats the only way a review would not be influenced by human emotion and personal preference..
EDIT: thats what i mean by reviews are not a sure sign of quality
not saying its the only reason, I just said it may be a contributing factor.. a games setting (or any media, not just games) can be a major factor in a persons enjoyment of the title based off of how interested they are in that kind of setting