With Bitcoin, you hold your own money. You control it.
With Ripple you control how *valuable* your money of choice is, with obvious limits (you're not going to pull the value of BTC itself up very far, but you will determine to a great extent how much BTC you have to spend)
With Ripple, you don't hold money. You hold debt, IOUs. You hold debt issued by a "gateway", a central authority.
A gateway is "central" in that it interfaces with other currency systems, in ways that normal individuals aren't going to care to. Without other systems to interact with, gateways would be unnecessary.
As it is debt, they can print as much as they want, when they want. (Aka debasing).
The catch being that your "printed" debt will only be taken seriously insofar as you are trustworthy. The free lunch isn't in the printing of the money, trust me.
...by someone who has no way of paying that. ie practically nobody people in the ripple network are not affected by that credit link at all. All this link is is an expression of utter trust between two nodes -- it is as if the CPU in a single machine is trusting the RAM in that same single machine. If either malfunctions, the other is probably not usable -- this level of practically infinite trust is useful to represent in some situations. All it means is that if you trust either, you're effectively trusting both.
With Ripple, OpenCoin Inc issued themselves 100 billion ripples. They promised to only keep half (50%) for themselves.
It's worth remding readers here that XRP is not Ripple, it is a special purpose currency used for spam prevention. If the half they keep becomes valuable, it will be because of the half they do not keep -- and if *that* becomes valuable, it will be because it is serving a use and adding value to the network. They will only prosper to the extent that they are increasing the utility of their userbase. Let the market sort this out.
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.
It is not *finished* yet. there is a difference between proprietary and unreleased software. It is true they can still change the rules -- they can wipe the slate clean (this is called a 'jubilee') -- which is why you shouldn't use a beta system for anything of serious value. You should, instead use villages.cc if you need Ripple to do something in a more verifiable way.
Ripple is v1.1 of money - building on top of existing central banks, and fiat money
Ripple alone could replace central banks. It builds on top of them only to the extent that it builds on top of *all* trust.
Their current marketing efforts are set to overtake and destroy BTC, with their centralized system.
Big words for someone who's got his own marketing campaign going on to discredit Ripple.
With Ripple, 1 BTC-Bitstamp is 1 BTC-Bitstamp.... - no site lasts forever.
And yet, in the long run we're dead. What we need is a system that works now, that uses trust that we have now, built on top of human relationships and human computer relationships we have now. It's true that not all people are equally trustable, and that if you're putting 1BTC through Ripple there needs to be a credit path between you and whatever it is you're trying to send to. This is by design. If you are not trustworthy, you will find it difficult to spend any significant amount through the network. You'll have to default back to Bitcoin and other systems, if so. However there are more transactions that are possible, more and better opportunities for trade -- and we are making them happen.