They are both peer to peer marketplaces so there will always be some scammers. Also consider that none of the people who have a good experience on these websites have a reason to look for bitcoin exchange review websites, it is the few that have a bad experience who go out of their way to leave reviews on other websites.
I'm sorry to say but the argument that only people who have grievances rate a product is pretty weak. I mean, look at all those reviews on Amazon or TripAdvisor... or even sites like TrustPilot or BitTrust. They are in the full range, good and bad reviews, too. Yes, it's easier to leave reviews on Amazon, you sing up to shop, but on the other sites?
Come on, guys! I expected better discussion from the premiere bitcoin community!