Having learned both VoiceOver for MacOS and Jaws for Windows at the same time, I feel that VoiceOver is much more integrated, faster, and less buggy than Jaws and Windows in general. It does have a higher price point, but you defintely get what you pay for, plus you can dual-boot with Windows if you find you need it for something specific.

Windows with NVDA. NVDA is not included but I believe it’s free. Mac OS has a built in screen reader and accessibility features. Ubuntu Mate has Orca included and enabled for installation. You can add Voxin voices to Orca if you don’t like the default voices.

I don't know, I think Arch Linux it's pretty easy to use and install...

Almost all Vision Accessibility tech is Software Based, not Hardware based—they’re all gonna be functionally the same. Mac tends to be more visually accessible than Windows, but that comes with an extra price tag.

Anything running Windows should be decent. Just throw NVDA on there. Mac OS is good for magnification but not so good for screen readers. Linux is beyond me. I only use it over SSH.

what type of accessibility? Do you need screen reading, zoom, contrast adjustments?