Ideal for small office server
Ubuntu is more proven on the desktop. I would imagine as a server in a larger organisation it would need to be supported by Oracle.
It probably is possible to install Oracle on it with some fiddling about, but as soon as you hit a bug Oracle wouldn't help you if it's not in their list of supported platforms.
For print, web and file services it would be a fairly good platform. So long as you aquire your products and printers to suit the OS.