Taichi's character is so well written that it almost makes every other character seem bad. That's only half a joke, the anime does such a good job of making you feel for Taichi and want to see him succeed. He's a character that is constantly beaten when he's down, so when he does have little moments of victory they feel so satisfying. With other characters like Chihaya, you're not surprised when she wins, and you aren't really surprised when she loses. It's fairly formulaic and you can usually pretty easily tell when the writers are going to have her win or lose. Although this isn'talways true, it's what you're dealing with most of the time. With Taichi on the other hand, it's always unknown whether he's going to pull through and win or fall behind and lose. (Although keep in mind this is only really talking about when his matches are actually focused on, and the same goes for what I said about Chihaya)