This book is highly thought of (I haven't used it myself)
http://www.amazon.co.uk/Practical-Fe...dp/B00M0OL2VU/
You can see the contents by looking at a previous edition. Everything said of Red Hat will be true of CentOS.
As you see, I use CentOS, having moved over the years from Red Hat (before it became commercial only) via Fedora (versions 1 to 14), and I'm a very satisfied user!