I've never heard of Pepsi Blue or Pepsi Holiday Spice, but yuck. Diet Pepsi is my drink.Pepsi Blue is...gross. I tried it the first time around and was not impressed. I'll have to give it a second chance and see if the re-release tastes different than I remember.
Another one to stay away from: Pepsi Holiday Spice. It sounds like it would be good. It was not.
Crystal Pepsi is where it's at.