They have a long list of things you can't complain about. One example is things that the seller can't change, like a loud train nearby. At least when I last used it if a single sentence in your review violated one of those policies your whole review was deleted and you couldn't submit a new one.

Interestingly their dispute process is very buyer-friendly, though. When a seller demands money in compensation for damage they often lose. I believe this is because Airbnb is on the hook if they can't collect from the buyer.