One major drawback of Ripple is that it relies on clients to maintain lists of nodes that are trusted not to collude. Bitcoin is not reliant on this assumption that nodes are not colluding. I could see a scenario where the NSA forces some of the most commonly used nodes to collude in order to comply with the law; even if users would suspect such nodes to have nothing to do with one another. In bitcoin, the NSA would have to take over the mining power. In Ripple, the NSA would just have to force a limited number of nodes to comply, since in order to ensure non-collusion between nodes, the client must choose from well-known nodes. If a client was to simply choose from a random set of nodes, there is no assurance of non-collusion. Ripple claims that this does not require trust, because we only need to be sure that nodes are not colluding, but it basically amounts to a dependence on a set of trusted nodes, because untrusted nodes cannot possibly be trusted to not collude. ie. Where are you getting your list of trusted nodes from?.... it has to be a trusted source. If you take your list of nodes from a public pool of nodes, then there is the potential for someone to contaminate this pool with a large number of colluding nodes.