Many people consider these two generations to be the best in the Franchise, but for different reasons. However, which do you prefer over the other and why?
I prefer G/S/C over R/S/FR/LG/E due to nostalgia, but if not for that, I would choose the latter. The latter has better gameplay mechanics, a better story (outside of revisiting Kanto, facing the remaining members of Team Rocket isn't really all that), and even a better Pokedex (and a much more challenging sidequest to complete the Pokedex at that).
I prefer G/S/C over R/S/FR/LG/E due to nostalgia, but if not for that, I would choose the latter. The latter has better gameplay mechanics, a better story (outside of revisiting Kanto, facing the remaining members of Team Rocket isn't really all that), and even a better Pokedex (and a much more challenging sidequest to complete the Pokedex at that).