dos - cli
But with custom ASCII interfaces of awesomeness
xp - gui
Lovingly designed by FisherPrice
dos - very fast to boot into
With the endless nerdy fun of echoing your own boot messages
xp - not so
But brought pretty pictures to booting!
dos - stable os
Unless you screwed with the wrong config file...O boy...
xp - not so
But usually readily fixable from a DOS bootdisk
dos - few 100kb
Which was a big resource hog
xp - cd rom size ?
Which was a drop in the storage ocean.
dos - boring
Unless you love Linux. In which case this is like the Godfather of terminal interfaces
.
xp - pretty
dos - hardware support sucked
Especially if you had a Soundblaster
xp - was pretty good
dos - was used on apples before pc's
Back when they were known as Macintoshs, and nobody knew what the hell a Mac or an Apple were.
xp - was used on pc's before apples.

- I cant think of any other usless bits.