With Ripple, as the server source code has not being released and it is still proprietary, OpenCoin Inc can change the rules and spend your money.
If they don't release the source code of Ripple server, there is no guarantee that the network runs the way they told you, it could just be another centralized e-cash, opencoin can withdraw at anytime and the network will stop to function.
If they do release the source code, then the Ripple framework would be infinitely replicable, anyone can just go and create their own Ripple network and release their own XRP, this could potentially mean that XRP has no value at all because it doesn't require a backup by computational power.
Interesting point regarding cloning the network -- and one which applies to Btc as well, yes?
Hardly the same, a bitcoin is, after all, a proof to the investors/users of your commitment and effort made to secure the network, when people buy bitcoins, a large part of the money goes to reward the miners, so people have at least an incentive to buy bitcoins even if they don't want to speculate at all-they know the more they pay, the more reliable and usable a payment network will be available to them, and the more reliable the network, the more people want to use them.(theoretically of course) Overtime an earlier network could establish a huge advantage over the later ones. So a real cloned network would have to replicate all the infrastructures in place, or get Bitcoiners, whose interests are strongly vested in the network to switch, such an endeavour would be extremely costful and make no sense economically.
A Ripple network, on the other hand, takes very little to rebuild from scratch, a validator costs nearly nothing to someone like a botnet operator, and they have incentive to stay honest and gain trust because their own XRP-clone currency could thus gain value and make money for them.
The XRP creators choose to issue their money in the "printing press" mode, there is no reason why others can't follow suit.
