Most sources from legends would say they're equal to each other, while being inferior to Yoda (obviously Sidious too)
It would come down to styles: If Mace can utilize vapaad the same way he did against Sidious, who is a greater duelist than Dooku, Mace will likely win the duel against Dooku. Although I think Dooku might have the slight edge in force powers, I don't think it would be enough to stop Mace once he disarms the count.... Sidious himself could barely do enough to slow Mace down while disarmed, what chance does Dooku have?
Originally posted by MythLord
For a major part of their careers, the two were played off as equals. By RotS, Mace would be ahead probably. Should be a nice fight, though.
I would say its a pretty close fight, as Dooku's elegance and peaceful nature is the perfect counter to Mace's vaapad.
But in the end I see Mace winning as he has the physical edge and slight duelling edge