I prefer manga over anime. With a lot of animes, they don't show many parts of the manga that I liked and things tend to be out of order. The manga is how the mangaka originally wanted their work to be and making them into animes can change the whole feeling. take for example Ceres: Celestial Legend (Ayashi no Ceres). In the manga, Shuro is one of the main characters. She is in many volumes and becomes good friends with Aya. In the anime, Aya meets Shuro in one episode and she dies in that SAME EPISODE. It's...disgusting. Really.
Fruits Basket is another example. Well, my example is a spoiler...so...I won't say it...I'll just say the manga reveals something about Akito that the anime doesn't. It's something rather important, too. Also, two characters who are members of the zodiac (the horse and the rooster) aren't in the anime. I found that odd. How can they completely cut out 2 characters, expecially, ones of the zodiac...?
And DNAngel is yet another example. The anime took parts of the manga and rearranged them in completely different orders. I hate that anime with a passion. I love the manga.
I also like manga better because you can hear their voices in your head and their voices sound like whatever you think fits their personailty. If you read a manga and then watch the anime their voices are probably a lot different and well i don't like that IMO. Example: Yuki from Fruits Basket. In the Japanese anime he...well, if I didn't know it was Yuki I'd say it was a woman. It's...terribly feminine. In the english version it's more man-like (Eric Vale ^_~) but it sounds sort of monotonous.
Manga's draw the story out more than the animes do. Sure they are longer and take more time to finish but they are also a lot better. There are many volumes of Ceres: Celestial Legend that are completely cut from the anime. I can't remember which volumes but the one about the white dog and such is not in the anime at all. It makes me really mad to see important parts of a story cut out of the anime.
Also, most English voice acting sucks arse. And watching them in Japanese is a pain because if you blink you miss what someone says.
The art in manga is always more beautiful than in the anime. Take Kyou Sohma from Fruits Basket for example. He looks a lot better and a lot more detailed in the Manga than the anime.
Plus, you can take manga with you everywhere you go. Can you take a DVD player everywhere you go? (Well, maybe if you have a portable one, but shh!)
And so goes my wonderful explanation of why manga is better than anime.
^o^