I can reliably pick out the difference between bottle, canned, and fountain Coke and Pepsi (all 6 variations). Out of the fountain, Coke and Pepsi are sweeter than their packaged counterparts (because the syrup is usually fresher and more concentrated); Pepsi tastes somewhat like a blend of Coke and watered-down Dr Pepper. Canned Coke and Pepsi have a metallic taste not found in its bottled or fountain counterparts (and this taste remains even if poured into a cup).

For bottled Coke, HCFS Coke and Mexican/Kosher Coke taste similar but not the same: HCFS Coke has stronger/bolder (one-note type of) sweetness but sugar Coke has a broader sweetness.

All versions of regular Pepsi have a cloying aftertaste.