I am a lifelong Mac user for audio/music production, as well as video editing and web design. But none of the Macs I have owned (including high end Mac Pro towers) have been able to run X-Plane at very high rendering settings with a decent framerate.
I purchased 3 PC's from X-Force PC specifically for my home flight sim and have been very happy with the results and support. Michael at X-Force PC is very helpful and responsive to any issues and can customize any machine to meet your needs and price targets. I have his higher end machine for my master machine with a 4K TV, all the Saitek panels, etc., and two of the mid-tier machines for the side views at 1080p.