Haikyu!! is entertaining, thrilling, and is ideal as a sports anime. It has minor flaws, but I'M IN LOVE. ITS AMAZINGx10000

1. Characters
The characters are different. Unlike what we'd imagine, the main character isn't a complete idiot who "works hard" and makes it happen, nor is he an amazing talent. He's just athletic and a giant ball of energy compressed into a boy. He has the right amount of flaws, but is, I guess, the right amount of 'awesome' to make up for it. The thing I like about this character, and all the characters in this anime, is that they're very easy to empathize with.
The side characters have hilarious personalities, and weren't just created as generic trash because they weren't the main characters. Thankfully. (My favorite side character is Tsukishima. Man, he's great.)
Almost all the characters develop in some way. The changes may seem a little quick to come, but it makes sense. Why did they change like that? It's never some dumb reason, you can understand why and how they develop throughout the anime. Thumbs up for that.

2. Plot
In retrospect, the plot is similar to most sports animes. (Joining a club, training to win. Win.) However, instead of just making the goal something cliche like beating a long time rival, there's a small twist! The thrilling arcs and interesting episodes, characters, and games keep the plot from falling flat into a spiral of bore.
I also want to cry in happiness and kiss this anime because THE PACE IS AMAZING. The fillers (if they were even counted as fillers) were short, to the point, and wasn't unnecessarily long *coughnarutocough*. They didn't even take up half of an episode. The anime also doesn't drag out the games for 3 episodes; the games are the perfect length to get the thrill, the suspense, and the relief while managing to still keep us on our toes for the next episode. Gawd, it's great.
As you might have read from the other animes, this anime is also hilarious. It's not overpowering the overall anime, but there's just enough to keep you laughing throughout the episodes and actually enjoy watching.

3. Art/Production
The art is very, very pretty. It doesn't look half-done at all (which was the problem I had with a lot of sports animes) and the characters actually look different, instead of having all the same face but with different hair and eye color. (...) Some have sharp features, some have soft, and they're all built differently so they actually seem like a group of real people.

4. Soundtrack
The opening is not bad, but it's not good. It kind of lacks the hype you actually get from the anime, but no matter, it doesn't hurt to listen to at all. The rest of the soundtracks are well-fit for each scenario as well.
The seiyuus (I watched the sub-version) are well fit for the characters. None of their voices are annoying. Yay.

-kuroinundertaker 2014 FROM CRUNCHYROLL  <3