For a long time I had a bias against Tsunderes, because most of them, honestly, are annoying. Plus, you had to add the moe factor. Most anime/manga nowadays have moe tsundere characters, which make us swirl in a huge downward spiral to moeblobland, a place where there are no original stories, plotlines are linear and characters have to be pigtailed tsunderes/ meganekkos/ over or underdeveloped lolis. But thank God there are always exceptions.
Good stories and well written charactes always shine in a world in which uniformity reigns supreme. Tora Dora! is a good example.
I was quite reluctant to watch the series, so I tried with the manga first (which are based in a series of light novels). The story is very common indeed: the petite uber bad-tempered Taiga delivers a love letter to the wrong person, Ryuuji, which due to his facial features looks like a yakuza. Both find out they have crushes on their respective BFF's, Minori (a really hyperactive wackjob) and Yuusaku (the perfect, too-good-to-be-true boy), and they decide to become allies to win the hearts of their respective love interests. We can guess how everything will end. Same goes with the anime, with slight differences.
But what is most attractive are the characters. Taiga is not a tsundere just because she likes it. She knows her flaws and weaknesses. She has a horrible, almost non-existent relationship with their parents (partly due to her temper), and hates being mocked for her size (I totally understand that; I'm barely 5ft. high) but stil, she tries to get along with people. She tries to go against her nature; same with Ryuuji, that all his life has struggled to be the opposite of what people may think he is: he is neat, responsible for himself and his super wacky mom, and a good student too. The entire cast fight against their flaws, imperfections and quirks in order to be better people. These characters progressively evolve in surprising ways along the way, and dare to show their soft spots, not being afraid of wat people will say. Because it's good to let people see you just as you are. Even if you reveal yourself as a tender tsundere.
Why do I think it's so good? Because it's real.