Atlantis was decent, better than Titan AE in my opinion (Probably do to its more original plot). Atlantis lacked more "grown up" thing though, like real character development. You never actually learned much about any of the characters. I wasn't that impressed with the animation either though, some of the backdrops they used looked too much like a painting and hardly matched the foreground.
One thing I loved was the music/sound effects, top notch!
"Treason doth never prosper, what's the reason? For if it prosper, none dare call it treason."
Sir John Harrington (1561-1612)