My name is Mandar and I work at MathWorks. We generally do not recommend buying a specific OS workstation to use with MATLAB. I think its better to consider system requirements while choosing the operating system to make sure that it is supported with MATLAB. Refer to the following link that lists the system requirements for the R2017a version of MATLAB.
If you have a specific question related to the performance of a toolbox in a specific setting that depends on the operating system, then I would suggest you to reach out to the MathWorks Technical Support Team using the following link.