Why is the manga better than the anime?

Today, I've been almost talked into trying to read the manga and not just watch the anime -- I'm not used to reading manga and am wondering why everyone loves it so much -- maybe it will give me some motivation to read it ! I'm currently caught up with the anime!

Which will I enjoy better as well? Best online place to read it? I know some have colored versions...?

P.S. I searched the forums and couldn't find a post like this, sorry in advance if there is one.