Exile vs. Anakin
Let's first consider what Anakin's down fall was: overconfidence. He thought he could make an uber high leap over Mr.Kenobi and got his limbs chopped off.
Now, what is Anakin's strength? Determination. It is said he was on his way to becoming a Jedi Weapons Master, and the characteristics of Darth Vader say Sith Marauder. He simply doesn't take no for an answer and will keep coming at you.
What is the Exile's weakness? In the case of LS Exile, it is also her strength: Empathy. She'll connect with anyone and anything and simply can't stand suffering. DS Exile? We don't know for a fact, but I think he/she was well on his/her way to surpassing even Darth Nihilus at the end of TSL.
In Anakin I see a potential Jedi Weapons Master with a ****load of Force potential.
In the LS Exile I see a passive Force Vampire and in DS Exile I see an aggressive Force Vampire.
Aggressive Force Vampires easily take down those with massive Force potential, so DS Exile would win easily. LS Exile would be siphoning Anakin's excess energy and would therefore win, but would not kill Anakin until the last minute.
Exile hands down. Force Vampiricy is in a league of its own, and the only person I see resisting it would be Kreia, who understands it and can even use a little of it.
As of 3/14/10, TSL is restored. The Sith Lords Restored Content Modification by Stoney and Zbyl has been finished and can be downloaded here