for me, a tough call. Pierce was much better offensively and right from the get go. Pippen needed a few years to get going. Pippen was a much better defender and rebounder. having said that, PP showed what he could do against one of the top players ever in Lebron in the playoffs. Pippen didn't really have to play against anyone on that level - he played with the one player of that caliber in the league at that time.
the eras they played in I think favored Pippen in terms of thinner rosters of the teams in the league at that time. of course, Pierce's early career had a paucity of talent in the East (when Sixers and Nets are getting to the finals with those rosters, the East was very weak) but over their careers, particularly during their peaks, I think Pierce played against better competition.
always felt Pippen was overrated and PP was underrated which would play into a poll like this if done nationally.