unfortunately, this question is too subjective to answer correctly.
each operating system has it's own advantages/disadvantages that would make it 'more suitable' for the specific requirement.
in general, UNIX is considered 'more robust' while WINDOWS is considered 'less secure/stable'.
WINDOWS is an 'operating system' that, historically used the 'processor chipset' provided by the INTEL corporation, 'evolved' from a 'local device only' operating system (MS-DOS) to a 'network capable' operating system (MS WINDOWS).
UNIX is an 'operating system' designed 'from the ground up' to emulate the characteristics of the 'mainframe' computer system.