Galahad, I'm serious about Bitcoin and Ripple, and I work to dispel FUD in the name of progress.
One person told me it is the perfect compliment to Bitcoin as it allows us to exchange our cryptocurrencies in a similar P2P manner.
Ripple is a way to trade Bitcoin in a decentralized manner. You have to trust that your gateway/s will remit, but you don't have to rely on them to trade your Bitcoin balances in Ripple. It's different than using an exchange site in conjunction with a Bitcoin wallet. You can trivially plug into Ripple yourself and move around all kinds of balances in a variety of currencies.
But many things about it worry me including, the central control over XRP supply.
OpenCoin's system is to award themselves 100 billion XRP, and distribute and sell 80 billion of these over time. I personally do not understand why people would object to this. Ripple is a distributed payment processing system, not a way for random people to receive free money in the form of XRP. However, the scheme for the distribution of XRP makes it likely that large amounts of people will actually receive some free money (this has already started as the Bitcoin community is well aware), which is very cool in my opinion.
As I understand it XRP are only there as transaction tokens so that people can see that money has been exchanged. The real cryptos exchanged must be stored by Ripple in some other way unless I have that wrong.
I call XRP the world's newest commodity money. It is both a "real crypto" and a token for paying network fees. Lots of info here:
https://ripple.com/wiki/.
They (Ripple | Open Coin) also have kept most of these coins and have abandoned mining (proof of work) without any similar alternative (proof of stake) in favor of central control. The absence of an alternative solution to this problem means for me is a red flag. It looks like a hierarchy of control due to the centralized aspect..
OpenCoin have pledged to GIVE AWAY 55 billion XRP, and they will be selling their own 25 billion XRP supply to fund their operations. So yes, they have "kept the XRP", and we must trust they will distribute it in a logical manner. But Ripple will be open sourced eventually, and if the community doesn't agree with OpenCoin's conduct, they can just start their own Ripple using the same technology. The time has certainly not come yet for criticizing OpenCoin over centralized control. When this time comes, my prediction is people will be saying: "Wow, OC did real good.".
With regard to PoW and PoS, Ripple uses an alternative solution called Consensus. Here's a video that explains it
http://www.youtube.com/watch?v=pj1QVb1vlC0&feature=youtu.be