I used to trust TrustPilot, but I have recently discovered for myself what others here say about it - that for its paying customers, it suppresses bad reviews and ignores blatant fake good review campaigns.
I tried to report some very obvious manipulation of TrustPilot ratings by a particular company, even providing proof. In May and October 2015 their rating was elevated from 3.6 to 9.4 by two blocks of five star reviews, one over 2 days and the other over 10 days. Most of the reviews were simple one liners by accounts with only a single review. At the same time as the first block of fake reviews, there was a posting in the client's own forums that urged forum users to elevate the sites ratings on TrustPilot.
No action was taken by TrustPilot. It would appear that the client in question is one of those that are a 'paid subscriber', In the meantime, I have observed a negative review in the process of being removed at the behest of this same client.
Looking more closely at a random selection of reviewed websites, it is obvious to me now that TrustPilot is not impartial, as it favours its paying clients, and its ratings are easily manipulated by clients and by other vested interests.