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I think it depends on what you like in the story.
In Gen 1-2 he was very much a novice, energized and cocky and prone to mistakes. Brock and Misty were his seniors, and he often needed help to overcome obstacles. It's the most "real" and boyish selection of a character.
With a few tournaments under his belt in Gen 3-4, he started to feel like the veteran to newer characters like May or Dawn. But Max very specifically makes fun of Ash's poor record, which is a fun way to keep continuity. It let's you know that Ash has a funny reputation in other Regions, and reinforces that "elder brother" feeling. These seasons also focus more on battle mechanics, with frequent tournaments and rivalries testing his skill. Between the Battle Frontier and Sinnoh League performance, Ash is arguably at the height of his journey.
Gen 5 was a "reset", and his first time leaving Poke-Japan. He reverts back to childlike wonder, but with all the edges of OS sanded off. He's just sort of nice and inoffensive now. This continues into XY, as much as BW gets hated on. Maybe the biggest difference between BW and XY Ash's story is the friend group. Where Ash used to always travel with older Gym Leaders, he's now surrounded by characters who look to him for inspiration and experience. Making him finally feel like a leader.
