I have been running one for siz years on my own and its damn hard, there are times in which you have to pay out for other peoples mistakes, for example I moved our entire operation from theplanet to softlayer and made sure I would have 8 days to check everything however softlayer had a communication issue between cpanel and exim which resulted in me loosing many clients and having to move them again to a backup hdd then to move them again once a os reload was done on the main hdd so there was alot of swapping and changing, of which I nearlly gave up. Not only did we lose clients from it but those clients we lost where a huge income for the organisation and in such made us have to go into our own pocket to fund everything else. Softlayer said when we asked them about it since it wasn't covered on their sla it basically wasn't there problem however we argued the point and gained some little respect due to it.

My point being if your in it just to earn money then your entering the wrong business and its hugely competitive. If your a reseller its easier but if your thinking dedicated machines then expect to be hit hard on the odd occasion.