Platform support (http://ceph.com/docs/master/install/os-recommendations/#plat...) and deployment tools have come a long way. In the past setup has been complicated (Ceph is inherently more complex than other systems), but it is getting much easier. There is also extensive documentation at http//ceph.com/docs, as well as very active IRC channel and mailing lists for support.
Ceph is much larger than just the file system (as the article points out). And while many Ceph products/subsystems are used extensively in production environments (RBD block store, RGW, and RADOS), CephFS isn't officially supported as production-ready.
Despite that, we run Hadoop on top of CephFS, and can deal with the occasional metadata server problem. CephFS is actively being hardened.