I was heavily invested in WDC, and got in early enough to make out well with that investment.
Speed is of massive importance; Bitcoin and many alts lack there. WDC solves for that issue.
However, I am not sure WDC delivers enough to make it a solid long term investment. It is great that Scharmbeck is trying to make it a serious option for regular usage, but I am not sure Bitcoin blockchain based systems can keep up with heavy transaction volumes.
In contrast, a lot of entrepreneurs are trying to solve for speed and other issues with closed centralized payment systems. I think Circle suggest a looming threat to crypto currencies:
http://finance.fortune.cnn.com/2013/12/27/michele-burns-circle/I thought WDC would be my long term investment, but decided to switch to Ripple, after seeing the broader set of problems it tackles.
Ripple has a great team, solid funding (Google Ventures, Andreessen Horowitz, IDG Capital Partners, FF Angel, Lightspeed Venture Partners, The Bitcoin Opportunity Fund and Vast Ventures), and impressive tech. I see Ripple Labs operating on an entirely another different level.
Ripple Contracts is a mind blowing concept for finance:
https://ripple.com/wiki/ContractsWorldCoin has a long way to go to compete in this space. I hope it does make major inroads, and do believe it holds genuine promise. Competition is great. Let the markets decide.