I think my favorite part of Adventure 01 is the arc where they go back to Tokyo. It really works well for the show. First you get to know the characters as they are thrust into a hostile land full of strange geography. They spend months walking through deserts, forests, and mountains dealing with a world they barely understand. Then they make it back to the real world and we feel their relief at finally seeing their families and having access to modern amenities again.
It really shakes up the show and makes it all fresh again. There is a completely different set of challenges for children with few monetary resources to cross a major city while also trying to keep their talking monsters from attracting attention from the crowds of people. We also get opportunities to see more of the lives of our main characters, get to know their families and how they get along. The stakes are ramped up as well. Instead of fighting in the sparsely populated Digital World, they are fighting in one of the biggest cities in the world. Every battle is reported on by the news and causes major destruction. I almost feel like this should have been the final arc, because going back to the Digital World after this feels like a major step back in tension.
It's a fantastic arc on the whole. I think it makes the show far better than if it had been only set in the Digital World, or even if it had started in the real world.
I really hate how the Japanese outro spoils the identity of the 8th child, though. Like as soon as the question of who the 8th child could be they change the outro to include kari and Gatomon. Come on! The show on the whole is terrible for spoiling itself though. There are very few evolutions that aren't spoiled before they happen in the show.