Pros and Cons: OS X Server vs Linux

They are generally incompatible.

You of course can set up equivalent services on each - but it requires knowledge of specific steps that may or may not differ on linux vs. OSX server.

Do you want to narrow things down a bit so we can give you a real answer?

What are your must have services?
What are optional?

It's really more a matter of how much time and money you want to spend on educating the people who will administer the servers rather than how much the initial software and hardware will cost. (Or any other cost/performance benefit that some review or other company might offer)

again, compatibility is relative. without further information, we can't say either way. in the sense that both OS X and other *nix OSes adhere to recognized standards, such as network protocols, they are compatible.

since you posted this question in two different areas, you might want to delete one of your threads. the other one's here.

powerbook G4 1ghz Mac OS X (10.4.6)