You just contradicted your previous statement of saying that "techs cant fix the problem" with "when your getting into OSX your not troubleshooting a mac per se since a mac is just the name of the computer your basically just troubleshooting a standard linux system ". The people that are going to be using these servers are in an IT environment that has *nix experience.
The hardware, as you stated, is standardized which makes it easy to dignose issues (not to metion the built in monitoring for the hardware). All that is left is the OS which is BSD. If you know unix then this should be no issue either. Also, Apple is going to be offering an option for 24x7 support.