What are the best OS ever of Microsoft ?

i use macOS and i love it

win3.11                     

This question is like asking new or vintage. 

I think it was Windows 7

I've always like Windows 7, even more than 10.

Windows 10  Current Version.

DOS 6.22 and XP.

I agree with L.E. Gant.  It was Windows 3.11.  (This version had an extra floppy disk that contained printer drivers.)

MSDOS 4.01.