Hmm ... I re-read your question ...
Upgrading a server (or not to upgrade) to a newer version is completely your own responsibility. However, a company like Red Hat also offers nowadays Enterprise versions of Red Hat Linux:
The main advantage of these versions is support. Support for these versions is 5 years for a customer with a support contract.
The other advantage of these versions is that companies like Dell, IBM and HP are very active in the beta-testing and hardware support (think SCSI drivers, RAID controller drivers, high-availability solutions, etc...) of these versions.
If you are willing to go with non-enterprise versions of Linux, and your management is _willing_ to take _those_ risks (try to get written permission to use a non-enterprise version of Linux, so they (management) cannot put the blame on you when things go wrong. Management always wants the cheapest solution, but must be _willing_ to take the risks and disadvantages than come with these kind of decisions).
I hope this answers your question a bit...