Who wins?
Which Reverse-Flash?
Which Flash, for that matter?
I don’t think there’s a clear answer to this one, though. If it’s Eobard Thawne vs. Barry Allen, then they’re meant to be closely matched. Maybe Barry would win on the, “It’s my book,” principle; unless the plot said otherwise.
Eobard Thawne aka Prof. Zoom
Barry Allen for The Flash.
OK how about Reverse Flash vs Superman. Again Eobard Thawne for The Reverse Flash.
Running, Reverse Flash wins. Even Wally West beat Supes that way, kinda. If Supes can fly, he wins because he always wins.
Wouldn’t a Reverse Flash run really slowly? Or does he just run really fast, only backwards?
No, that would be Bizarro Flash. 
[QUOTE=The Tick]
You can’t outrun justice -
[/QUOTE]
…
The Reverse Flash wins because he cheats. He grabs a knife and runs through a town, slicing people as he passes, and the Flash, hero that he is, has to spend precious milliseconds getting the people to hospitals. This happened in the comics when, after a long time after Iris’s death, Barry was going to marry Fiona Webb. Thawne raced him to the church, taunting him that he was going to kill Fiona before Barry could get there, and slowed him down as mentioned above. Barry saved Fiona, but had to publicly kill Thawne to do so.