This show has almost everything you could ask for. An interesting world that begs to be explored, multi-faceted characters, snappy and well-written (and well-delivered) dialogue, solid pacing, and even a surprisingly competent score. The story is fairly straightforward in the first season (think Tolkien), but the entertainment comes mainly from character interactions and development, as well as the world building, rich set pieces, and impressive sense of gravity the show manages to impose at times. It's not perfect, of course. Occasionally, the dialogue feels a little stilted, and the 3D animation will feel a bit uncanny to some. But from a technical standpoint, the animation is extremely well-executed. Personally, the characters move naturally enough, and the world is beautiful enough, that the style won me over pretty quickly.
At the end of the day, if you were a fan of Avatar: The Last Airbender's globe-trotting not-serious-but-also-sometimes-extremely-serious fantasy-epic style (and I lament to mention that show, as this one really should be considered a completely separate entity), this one starts strong and seems poised to deliver. If the current level of quality endures, this will surely be a very well-remembered series.