Why do you like your OS?

[tlt at ihldt.UUCP]

I would like to find out what people like/dislike
about their favorite/least favorite operating system.
What are some of the neat features/idiosyncrasies
of the OS you like/dislike the most.  In particular I am 
interested in the following:

     UNIX
     MVS
     VMS
     MSDOS
     CP/M

I am trying to understand why my alma-mater just
bought a VAX 780 and has decided to run VMS instead
of UNIX.  One of my old professors there told me 
that the engineering students wouldn't understand
how to use UNIX (too complex for the engineering type
I guess).  He also said that if UNIX did not
evolve into a more user friendly system that MSDOS
would become the default standard OS for micros/minis.
Not at all familiar with VMS or MSDOS I am puzzled.

I assume the only reason people run MVS is because 
that's what they're used to. ie have used IBM for
many years, why change now.  Similarly for CP/M,
that's all there is for the 8080/z80 machines.

If I missed your favorite/unfavorite OS don't be
shy.  Send me mail anyway.
If I get enough responses I may summarize to the net.