Ignoring the technical aspects of the games (i.e battle mechanics, graphical quality, etc), which region and map is your favourite? Which one was the most fun to explore, felt the most organic, and held the most adventure?Conversely, which one was the worst? Which one is the least inspiring and discourages you from wanting to return?
Personally I don't think the series has ever succeeded in surpassing the maps of the original GBC games. The later games had more fleshed out and more atmospheric regions, but linearity killed the sense of exploration.