Sizemore may not have the speed of Podsednik but he is a better overall hitter and scores more runs as a leadoff man due to his extra-base hit power. He also plays better defense at a tougher position (CF). Sizemore is a much better player than Podsednik and a better leadoff hitter. There is really no contest.
Sizemore will be a great player for the Indians for a long time. It would be sweet if Anderson turns into a similar player.