X-Men is the third of the Marvel Anime adapations and is without doubt the best so far by a wide margin. The fourth series, Blade, will have to be very special to improve upon X-Men, which has a nearly perfect trifecta of story, character design, and animation.
But the story is where X-Men really outshines the preceding two series. The story seems like it is actually written for a 12 episode series with just the right balance between action and plot development.
I highly recommend this series for both anime and X-Men fans alike.