When I was younger I used to read American comics but now I don't really do so as much. The ones I used to like were the superhero ones like
X-Men,
Spiderman,
Gen13 and other ones of that sort.
Now I read some manga here and there, my favourites being
Beck and
Berserk. I think the main difference is that manga stories usually end up telling a more complex tale that isn't always designed to carry on indefinently. The American comics are usually episodic or have small arcs but don't really do much to tell a story with a definite beginning and end to them. I like stories that I know are going to have some sort of conclusion and are working to continuously get to that end.
I also like how Japanese mangaka both write and draw their work. It seems to make the whole process much more concrete and cohesive. Rather than having a whole team working on one comic a system using one main creator and a few assistants probably allows the work to stay truer to the story being told.
The only American comics I've read recently are
Transmetropolitan and a little bit of
The Maxx which is really neat. They made a really good cartoon of that as well.
I also agree with meryl in regard to the Japanese influence on American comics. It only really serves to weaken the individuality of American comics when the artists are trying to recreate a Japanese style with many of the works coming out now. Some of them are genuinely influenced and that's alright. When the penciller has grown up watching anime and reading manga it's natural that some of the stylistic undertones would come out in their work but when they try to recreate a style it only weakens what makes American comics unique.
Also, meryl, the word "mangeeru" doesn't mean anything as far as I could find. What's really stupid and irritating about that is that it seems like they tried to spell manga in a English-Japanese romanization way which seems condescending, really. If it means something that I don't know then I feel dumb about saying so but that's the only thing I can think of. What is sort of funny is that the similar word "maneru" means, "to imitate" or "to mimic" which is exactly what they're doing.