Hi,
As for using RHEL verses CentOS, here's my suggestion. RHEL (RedHat Enterprise Linux) is designed to offer companies the extra assurance that if something was to go wrong, the company would have access to professionals who can fix the problem quickly. This is very important if you have dozens or even hundreds of employees (or worse customers) trying accessing your server when it goes down. Financial costs can skyrocket very quickly.
For an individual, it may not make sense to pay for this extra support as the financial losses due to an OS/software issue can be quite minimal. For most individuals, it would merely an inconvenience. And if it takes a few days to get back up and running, probably not a big deal. So the lack of a phone number or e-mail address to get instant support is unnecessary.
I look at it this way, what would cost me more, having the computer down for the time it would take to reinstall the OS, software, and restoring backed up data, or the cost of a year's tech support.
Hope it helped..