I prefer manga. I just enjoy reading at a leisurely pace.
Manga also feels like you can understand the storyline and the characters. I feel like I can get a better understanding of both when reading than watching. A lot of animes come from mangas, so, I prefer to read the manga, before watching the anime and see what they have changed, added, or removed.
Manga also feels straight to the point, without any episode fillers or the like, such as DBZ. I loved the DBZ anime, but a lot of the episodes feel like they are just taking up room. I remember watching an episode of the Buu Saga, and it took them one whole episode to "power up". When I read the manga, they took like 4 panels at most to get where the anime is.
I don't mind watching anime from time to time, but again, I prefer reading and being a bit more active than watching.