Not a huge fan of either...but I would vote for Pop over Zooropa. I am still not sure how to place Zooropa in the U2 canon...it kinda stands alone to me as something completely different than anything else at all. I have trouble connecting with much of Zooropa to be honest...some of the songs have a cool beat and sound, but I don't identify with them the same as War/TUF/TJT.