Avatar is really good. Especially for a NA show making use of anime styles... I think a good part of how they managed to get that to work (where so many have failed) is that they kept things straight. They didn't try to duplicate "wacky" anime stuff, instead they did things like take inspiration from works like Miyazaki. Not that there isn't humour (there's a lot of it), it's just that that part came more from themselves and not an obvious attempt to copy anime humour.
I wouldn't go so far as to say that the ethnicity is totally blurred, though. Once you ignore the eye colour (which seems to be partially based on the element the tribe bends... Kitara is a water bender, Zuko is a fire bender), a lot of the blur is gone. For example, the Water tribes, which live at the poles, resemble the Inuit in look and dress. Water bending style, however, is clearly based off of Tai Chi (so there is that level of blur). In fact, each element's bending style is based off of a different marital art (with some room for exceptions... Toph is a non-standard earth bender based off of Mantis style).
Re: Would you let us know what you thought of it?
I wouldn't go so far as to say that the ethnicity is totally blurred, though. Once you ignore the eye colour (which seems to be partially based on the element the tribe bends... Kitara is a water bender, Zuko is a fire bender), a lot of the blur is gone. For example, the Water tribes, which live at the poles, resemble the Inuit in look and dress. Water bending style, however, is clearly based off of Tai Chi (so there is that level of blur). In fact, each element's bending style is based off of a different marital art (with some room for exceptions... Toph is a non-standard earth bender based off of Mantis style).