"SL didn't pass the muster in our env in terms of a drop in replacement for Centos. On the other hand, we have simply dropped in Centos in place of RHEL w/ o issue. Our env is a rather complex CGI/VFX based pipeline that is not trivial to design or support. So if you have 12-24 months, I'd wait, seriously man, what's the rush?" I have to provide a reliable and scalable infrastructure, and that requires a reliable provider / updates. While I do not need Centos 6 today, this development cycle has certainly raised questions as to whether the development process can be relied upon. The whole "when it's ready" mantra works well for academic/individual users, but you can't plan business processes based on it.