I attended OpenStack conference for 2 days this week. I have to say I was really impressed by the momentum behind OpenStack: 3,000 energetic people from 50 countries came all the way to Hong Kong! It smells like VMworld in the early days. :)
Based on my experiences with OpenStack code base and various discussions with folks in HK, my assessment is OpenStack is still far away from the "prime time", despite so many companies went on stage touting their production deployment. In my opinion, a lot of people use OpenStack because it is the only game in town for what they want to do -- I don't believe there is an equivalent commercial product.
People often treat vSphere as the commercial alternative, but I look at OpenStack to vSphere just like NoSQL to Oracle -- OpenStack is solving a fairly different use case and targeting very different audience. Just like Oracle was never designed for scale-out database, vSphere was not designed for the level of scale-out current OpenStack users want.
For those who put OpenStack in any serious deployment, they must have invested tremendous Dev cycles for the deployment. So in a way, if you add up the Dev investment, it is not saving money, not today! They use OpenStack as a framework not a turnkey solution, and build/modify things according to what their own needs. The base distribution is not quite "complete" at this point, for instance, among other things, the it does not have an installer today and the TripleO project is targeted for 2014.
Finally, I believe the availability of the source code, the relatively meritocracy based community with lots of passion, and the momentum/sexiness of the brand name do give people a lot of imagination on the potential. I suspect by the end of 2014, we will see OpenStack distribution with enough bells and whistles for those who cannot afford to invest their own "Dev" cycles.