Is it actually something usable? I don't know of many active users of it.
Depends on what you want to use it for. Run age-old hardware requiring age-old NT-only drivers? Sure. Run modern games? Forget it. And for the age-old hardware stuff (think control board for an electron microscope or something) people usually use FreeDOS, the number of devices that specifically need 32-bit NT is comparatively small. And that's if they even upgrade at all often it's just easier to slap an RPi in front of ancient hardware to isolate it from and adapt it to modern surroundings (but yes mainboards with ISA slots are still getting produced, electron microscopes are expensive).
Or there's ReactOS: https://reactos.org/gallery/
Is it actually something usable? I don't know of many active users of it.
Depends on what you want to use it for. Run age-old hardware requiring age-old NT-only drivers? Sure. Run modern games? Forget it. And for the age-old hardware stuff (think control board for an electron microscope or something) people usually use FreeDOS, the number of devices that specifically need 32-bit NT is comparatively small. And that's if they even upgrade at all often it's just easier to slap an RPi in front of ancient hardware to isolate it from and adapt it to modern surroundings (but yes mainboards with ISA slots are still getting produced, electron microscopes are expensive).