Bane stomp.
Srsly. 😐
Bane has the advantage of superior saber technique, Force mastery and (assuming RoT) near impenetrable Orbalisk armor. Anakin has a lot of latent Force strength. That's it.
1. Saber: Bane by miles- I don't see Anakin/Vader getting past Bane's armor to score a hit on the head or wrists.
2. Force: Bane, if he plays it smart. Anakin doesn't have Force Lightning (I think) so he is stuck to Force Choke/TK. Neither of those attacks are likely to phase Bane. Although the Choke might be interesting (Force power to punch through a shield vs. instakill moon-moving might) TK is simple to counter (a la Mace in Shatterpoint).
3. All out- Bane takes this. Anakin is no pushover, but Bane is a tank that simply will not die. The only way I could see Anakin taking even 2 or 3 out of 10 is if his superior Force reserves allow him to tire Bane out- an unlikely scenario as Bane has shown considerable stamina as of RoT: he fought 3 augmented Jedi Masters (Ok, 2+ Johun) to a standstill at the same time.
Hasn't this been done before?
Bane
Bane
Bane.
I want to say anakin for sabers, but no because bane is a formidable duelist and has the gay ass orbalisk armor.
While anakin in his clear state of mind was able to make a joke out of dooku, he isn't going to do the same to bane thanks to that ****** ass armor of his.