Since these reviews are not written by robots, there will be biases.
As the main writer here at Better Zombie, I have a huge bias and am not afraid of that. While I try to be impartial and give everything a chance, if it stings me the wrong way, I will not support it. Since reviews take me a long time to write, I typically won’t bother with writing about something unless I have some research behind it, but even still, there are probably holes in my arguments. It’s fine to point those out, because it’ll get to a better review overall.
If a review could be particularly biased, I’ll note it.
For example, if a record label sends me a review copy for something, then I’ll make note of that in the review. The agreement during the conversation prior to the review will include this clause: “I will not consider branding or friendship in these reviews. I will provide my usual thoughts as I review them, whether I like them or think they’re trash. Is that OK? If not, this review will not happen. I am not in the business of telling lies.”