I guess I don't really see "I don't want to trust anyone" as a viable position. XRP's structures (at present) makes it very clear who you're trusting -- Ripple. Bitcoin's structure plays a game of hiding the ball. You don't have to trust anyone it says, but the reality is you do. As has been pointed out, you're trusting large scale miners to not collude. You're trusting the Chinese government (where most large scale miners reside) to not exert undue influence. In short, you're trusting a system that obfuscates the parties on whom your trust relies.