Here are my thoughts:
Orange: Slightly worse than Kanto but still good overall
Johto: Much worse than Kanto and Orange
Hoenn: Improvement over Johto but not as memorable as Kanto
Battle Frontier: Mostly the same as Hoenn, maybe slightly worse due to the rushed aspect of it and lack of Kanto references.
Sinnoh: Improvement over the entire show in many areas, but a step back in group dynamics, humor and pacing.
Unova: Worse than Sinnoh, possibly worse than AG, about the same as Johto in some regards, could prove better when it ends.