Revan would probably win.
1. Force Lightning doesn't exactly play well with Vader's Suit.
2. Revan utilizes 2 sabers, while Vader has brute strength Revan has the speed advantage.
3. Revan took down the Star Forge defenses and then took down Bastila and Malek, I don't think Vader could have accomplished that.
4. Fact that Vader killed Younglings would probably annoy Revan, putting it mildly.
It would be a close match, but Revan probably has the advantage.
1. Vader tweaked his suit to resist force lighting, however he couldn't resist Palpatine's lighting because it was the strongest ever.
2. Doesn't really help much, since he fought Galen(clone) who used two sabers and even then he wasn't really trying fighting disinterested.
3. Hmm...Vader took down the jedi temple with just a legion of clones, he then later went on to take over several worlds and hunted down whatever jedi he could find after Order 66.
4. Again...yes he did, but he also killed all the jedi masters in the temple(save for Shaak Ti who ran away)