Read this article from Space.com. It appears that NASA is doing away with fix priced contracts in regards to commercial crew transport. They are going to a Space Acts Agreement model, which will allow them to pit the private companies against each other for the best price. In exchange, NASA will have less input into how the spacecraft are designed (except in regards to safety).
I think this is a great idea for two reason. 1. Having the companies compete creates a truly capitalistic environment which will drive down cost and increase innovation. This will ultimately benefit everyone as each company tries to outdo the others, which will hopefully lead to revolutions in technology. 2. With NASA giving more freedom for design it will also allow more innovation and unique solutions on the parts of the scientists and engineers at each of these companies.
Overall I would say this is a very good choice on NASA’s part.