Dooku is finesse and efficiency; Vader is strength and power. But Darth Vader, in Street of Shadows (the new Coruscant Nights book) is able to evade the unimaginably lithe and agile assassin Aurra Sing when she, in a fit of rage, attacks Vader. The omniscient narrator goes on to detail that he is toying with her, never attacking, and keeps his lightsaber at his belt. He dodges and evades her attacks and lightly taps her instead of beating the hell out of her, demonstrating the fact that he could immobilize her at any given time. Moreover, after a while, Vader evades her and uses a casual surge of telekinetic energy to throw her to the floor and keep her there.
It says that the guards out in the hall way are nearly thrown off their feat, even though the concussion wasn't directed near them at all. Also in that book, he uses the Force to summon one of Sing's lightsabers to him, grips it, and overloads the blade through sheer will, leaving it a useless metal hilt. Sing is in awe.
Yeah, Vader's badass.