Superman all the way.
Vader is an easily manipulated, not too bright, severely injured cyborg hopelessly wheezing and clunking around. Plus, he's heartbroken! All he's got left is "The Grip" and some clumsy remanent of swordsmanship.
Vader would have no chance at all.
Now Superman against:
Yoda, Mace Windu, Lord Sidious (Palpatine), Count Dooku, Qui-Gon Jin, Obi-Wan Kenobi, General Grievous or even Darth Maul.....
Absolutely cut to ribbons. They'd be picking tattered shreds of Super Mincemeat out of the Phone Booth for weeks.
Even Avon from Blake's 7 could probably get the drop on the Man of Steel.
Have Fun,
Keri
PS> Jar Jar Binks could probably defeat Superman by accident.