I'm away from the computer during a vacation, but I'm making a quick exception today. Clearly I'll have to catch up later - there's a lot out of recent prize news out there.
Space Politics has a discussion on "How to Build a Political Consensus for Space". Prizes are just one facet of the discussion in the comments, but I'll include some brief excerpts on that topic.
Mark: "COTS and the Centennial Competitions are both things that would have been unimagined in the bad old Goldin/Abbey era."
Anonymous: "Despite promises in Griffin’s early speeches, Centennial Challenges hasn’t received any new funding in years. The program is running on fumes. It was started under O’Keefe, and Griffin has all but killed it through neglect."
Anonymous: "Even today, NASA should not be allowed to get away with one, underfunded COTS program. Why isn’t NASA using Zero Gravity Corporation’s vomit comets? Where are the commercial suborbital microgravity solicitations that Griffin promised? Now that Orion is light enough to fly on commercially available EELVs, why isn’t NASA using those launch vehicles? Why isn’t NASA soliciting commercial demonstrations of in-space propellant provisioning? Why isn’t NASA soliciting or offering prizes for commercial robotic demonstrations of resource extraction on the Moon?"
There is a lot more in the comments. Much of it deals with whether or not NASA should be melting away its robotic science program and reducing its human space program to a monolithic government designed and operated space trucking "business", or should develop more smaller missions and use (or when not available, provide incentives for the creation of) commercial space services. Prizes are one part of this more complex issue.
You can tell where I currently see the issue by my view of NASA's current approach as akin to betting an entire baseball career on getting a major league home run on a single pitch with no practice that season. However, you should see the full discussion and the links in the original post so you can form your own opinion.