Regan was possessed by Pazuzu, not Satan. He claimed to be Satan at one point, I think, but as demons tend to lie, that's what he was doing. While possessing Reagan, Pazuzu could levitate her body, speak in an altered voice, gave her superhuman strength, and could move move small objects telekinetically.
Carrie, on the other hand was a TK whose limit of her power allowed her to deflect an oncoming car, set it on fire, and pull down a whole house around her herself while she was dying.
I say Carrie whups Reagan pretty handily.