the fillers mess with the anime though like the arc right now with the noah she has yet to show her self in the manga though she is in it but we don't know anything about her in the manga
yeah, and things in the beginning happen a bit differently and in different order; like we see allen's past before his first mission and before he joins the Order in the manga, and in the anime we see Allen's past after he joins the Order and Linalee' there too. and, yes many fillers...but the reverse novel 1 is in the anime...
I always watch all the anime I can then i read the manga to get further and then I can tell the differences for you it is just preference since D. Gray-Man anime isn't far from the manga but it does have fillers...yet some of them are really funny in my opinion others kinda suck to me >>.
remember D. Gray-Man fans discuss the manga and anime at ROI and enter the contest too click me!
Manga to me, is always the better option to take.. Anime is only to listen to soundtracks and hear the voices of the characters.. ^^ Oh! And see them in colour..