1. How much do you bet?
2. Mastercoin distributed exchange is for MSC<->BTC trading, this one is for trading securities. It isn't the same thing, is it?
3. The problem with Mastercoin is lack of finalized specification. Difference between multiple implementation can result in monetary loss. On the other hand, in case with colored coins, an implementation of color kernel can serve as a finalized specification: you can just keep using it, it will never change. We can implement other kernels, but they do not invalidate older kernels, different kernels can peacefully co-exist.