I believe only in TrueUSD, because Bittrex team believes in that and I trust them. I don't beleive in Tether, because their policy of issuing money is not transparent, they refuse to conduct an audit - I don't like this.
I heard about new stablecoin - Circle, I believe in that too, because this is token from Goldman Sachs(Poloniex).
IMO trueUSD is a joke same with basis too. I'm a personal believer in Havven just based on their credibility as a company. For me that stems from the team, partnerships, vision, dev, and ideologies. You should read up on them because they're launching nUSD on june 11th which is a huge deal