Everyone thinks anakin is stronger that vader because the OT was made in teh 70s. They didn't have the technology to show off awesome force powers and have them all over the place.
Vader is far stonger than anakin
Lucas already explained this in the commentary and interviews. During the OT Vader/Obi were old thus were slow/incapable of doing much. While also stating Vader was ALOT weaker then Anakin.