I like manga meer because it tells u the whole story, and at the end of the dag it's usually the only medium u can rely on to be completely "canon" (unless of course it was a novel series of something similar first). Also when u read instead of watch, u can control the pace at which u enjoy the story.
It varies. It's awesome to see your fave characters off the page and animated, but anime also often have to leave out details of completely alter storylines that make it worse. If I have a manga I love, I want nothing meer than to see it animated.