Kanto for personality,Hoenn for team.
Ash made it to the top 8 of the Ever Grande Conference without the reliance of reserves,no real ace,no gimmicks and almost defeated the winner of the Hoenn League in Tyson who also had a balanced team.
Ash's Sceptile is one of my favorite pokemon in the series,it has an aloof and laid-back personality which I can relate to.Back when it was a Grovyle it had a case for being Ash's strongest pokemon in the Hoenn region up until Tailow evolved.
Swellow has the speed and durability to take a lot of punishment,it's also been said by Brock that it's as stubborn and determined as Ash.
Glalie didn't show up until late AG before the Hoenn League started.It's arguably Ash's strongest pokemon at this point,it had a consistent showing at the Hoenn League.
I'd say the Hoenn region was the only time where I actually cared for Pikachu,I could probably also say the same thing for it back in Kanto but in Hoenn this is where it got away from the Kanto team and got more development,because for me back in OS it was overshadowed by Charizard,Bulbasaur and Squirtle.
In early AG Ash was teaching it how to use it's Iconic Iron Tail,at the time Pikachu could only use it only once or twice before it'd stop working.