This is an acceptable operating system if an application you require supports Redhat and nothing else. If that is not the case there are better options available with SLES being my top pick.
Good base package selection
Supported by most third party applications.
Overpriced. Especially when compared to SLES or Ubuntu Enterprise both of with are superior to Redhat.
Redhat is too greedy. If you have an issue and try to look for help you actually have to login to their site because they are so greedy they require logging in to see solutions to a problem.
They put almost no effort into customizing the OS to look nice and be usable from the default configuration which requires editing profiles, and configuration files for a lot of minor things that most distributions do for you. An example of this is the lack of a colored PS1 prompt even for root.
By default host entry is added to /etc/hosts. NetworkManager is enabled by default and it wants to put the FQDN into /etc/hostname because it is too stupid to know that hostname should not return the same results as hostname -f. So adding a host entry is another thing that must be done which you should not have to do.
Another thing I hat is the unnecessary packages that get installed by default. For example, since when did most servers start needing wireless drivers installed?
Although Red Hat's commitment to providing long-term security support for packages is extremely commendable, the real world unfortunately moves somewhat faster, and this often results in many packages becoming increasingly stale over the lifespan of a Red Hat major version, and, in particular, making it difficult to install many popular web packages (somewhat ironic for a distro marketed as a more secure distro for servers). It is often necessary to scour the internet looking for third-party repositories to install newer versions of key packages, when instead, it should really be for Red Hat to make newer versions available as optional installations for those who need newer (not necessarily the newest) versions.
My personal choice would be for Debian or Ubuntu LTS instead, which combine both reasonable long-term support with the easy availability of newer software.
solid distro for production environments. Stable, stable and stable again as well as secure. Support is very good. Knowledge base is actively maintained. My OS of choice where clients demand high uptime and with demanding SLAs!!