Ripple is all about traceable, centralized payment system which is opposite to BitCoin which enables decentralized, anonymous P2P payment.
There are many Ripple-like payment systems in the past (e.x eGold). I don't really know what is the point here.
Well, bitcoin seems to depend on cenralized exchange instead which is Mt. Gox... IMO, the real strenght of bitcoin is media coverage, something the older currencies and payment systems lacked in the past. Guys behing Ripple know it very well.