I'd like to quote dancupid and myself. (this was 2013)
Ripples are a ponzi, and that's their saving grace, since everyone knows they pre-mined 100 billion of these - so ripples are the worst investment in the world - they don't want us to invest. They've made it explicit. 'Don't invest in ripples, invest in ripples and make us rich'. It's built into the system.
Ironically that's why ripple may succeed.
You don't "invest" in ripple, it's not a currency. It's a debt-tracker.
I was quite wrong, I have to admit: you
can invest in ripple. Just make sure you know what you're doing. There is a
huge premine and XRP are only meant as "spam prevention token" to enable the IOU-based functionality (trade, transact, exchange,...)