I notice they've stopped putting dates on their manifest for future flights.[2][3] SpaceX is doing a great job, but they're behind their own schedule. They're two flights behind on ISS resupply, and launched less in 2014 than they'd planned. They may be having scaling problems with their organization. They have a a product and customers, but can't meet demand. This may get better once they get their own spaceport in Texas finished.
[1] https://web.archive.org/web/20130802104411/http://www.spacex... [2] https://web.archive.org/web/20141030024140/http://www.spacex... [3] httpd://www.spacex.com/missions