What Revan?
End of KOTOR Revan- Revan here is the champion of the light, so Vaapad won't be nearly as effective. At the same time Mace Windu has far more experience at this point. Mace has the edge.
Novel Revan- Although Mace has more to draw on with Vaapad than KOTOR Revan, Revan's power in the force will trump Windu.
TOR Revan: Windu, at this point Revan is very much tainted by the Dark Side and is more grey than he's ever been. Superconducting Loop incoming.