Ted Williams is a better player than Joe Dimaggio. I don't even think it is close. In fact, most experts put Ted Williams in the top 4 position players all time right there with Ruth, Mays, and Bonds (at least those that still recognize Bonds).
EDIT: And just so you know I'm not making stuff up, here is the ESPN list of the 100 greatest players of all time. http://espn.go.com/mlb/feature/video/_/id/8652210/espn-hall-100-ranking-all-time-greatest-mlb-players
Ruth, Mays, Bonds, Williams are the top 4. Aaron is 5th. Followed by Cobb, Clemens, Musial, Mantle, and Wagner. Joe D. is 21st on the list. This was made December 4, 2012 so it is recent and obviously doesn't discount the PED era.