For me it really depends on what mood I'm in. They both have certain aspects which appeal more at times, like Mangas have faster paced storylines which you can read at your own speed, whereas with animes you're sometimes forced to go a bit faster than you'd like to. Mangas can also take more detail into account with the drawings and are usually more visually stunning. Let's take akira for example. That's in 6 books, and these are big books. But the film, the first three books are told within about 90 minutes, and the last half hour is severely rushed and spoilt if you've read the books as they just cram it all in. As with most book to film conversions, you lose a lot of the story as it's hard to fit it all in. But there we go
