I saw Steamboy last night and I'd say the movie was just good. Well, average good is more like it. The story was slack and straightforward, and the characters were really one-sided, one-dimensional, and cliched (esp. Dr Lloyd, voiced by Patrick Stewart, who was the total epitome of morality in this piece). Some characters were more annoying than others (I point at Scarlett and Dr. Lloyd!), but the animation and CG effects were nice and all.
Steamboy is really action over plot and characters. I also felt the last 20 minutes got somewhat tiresome and exhausting since it was endless repetition of steam pipes bursting and exploding.
The English dubbing did its job alright, although I would have preferred the original Japanese dialogue. (I need to make a correction in that the U.S. version of Steamboy is being shown in both English dub and original Japanese dub....it just depends on the place that's showing it. Also to note is that the English dub version was trimmed-down by 15 minutes....which I find odd. So, if you see Steamboy, try to see it at a place that showing it in it's full Japanese, unedited 2-hour run-time form.)
Action fans will dig the latest from Katsuhiro Otomo. If you're going in expecting something different and deep, you won't find it here.