Seen the news earlier about Mt Gox and Dwolla?
It takes one court order from the DHS to seize all your Ripple balances - because Ripple is centralized, and it's closed source. Joel isn't going to go to prison for 10 years just so you can have your XRPs and imaginary BTCs.
If you haven't, read RippleScam.org - and listen to it now until when the crackdown on cryptocurrencies happen.