Running it on non-Apple hardware is legally questionable at best (the EULA forbids it, if this part of the EULA is applicable in your country is a question for a lawyer), Apple doesn't do server hardware anymore, it costs money and you don't get support or special software from Apple for server-usage for it, and since nearly nobody runs it as a server OS it probably isn't very high on the priority list to support that usage for other software vendors or open-source project.
A lot of things probably will work well since they are made to run for developer usage, but if you do not absolutely need integration with something apple-specific or just want to reuse an old mac lying around for a hobby project it doesn't give you anything over other OSes as a normal web server.