This is the first issue of a great series! Off to a slow start, the drawings get better as the story goes, as well as the dialogue. As a matter of fact the second issue features many moments that seem like they come straight out of the show. If you love the series, I highly recommend these comics.
The comic series is broken up to 3 issues per storyline. I found this first storyline to be kind of like the author just getting their feet wet in the Avatar universe. The second story, The Search, is where it really starts to get good. But I still recommend the Promise just so you can be treated to Toph's Metal Bending school. It's perfect! There are also some other story elements that you might be sorry you missed if you skip ahead.
And, I know it's noted elsewhere, but the creators of the show work closely with the creation of this series as well.