I wasn't reading the book in the car as Leila did, but I had a similar can't-put-it-down-oog experience. I spent the whole afternoon carrying the book from room to room, shamefully neglecting my three children, in order to devour it as quickly as possible -- and I was not a bit sorry that I did.
Meg Burden's style is clear and lyrical, her descriptions vivid (I could feel the cold, the pain and the grief right along with Ellin; and whenever she had a warm bath or a delicious meal, I wanted to lie back and say "ahhh" myself), her worldbuilding rich without ever becoming info-dumpy, and she shows a wonderful talent for creating diverse and distinct characters without turning them into caricatures or giving them annoying dialogue tics as some other authors do. The action scenes are taut, well-paced and gripping, while the central question of why the Northlanders hate the Southlings and vice versa is both well laid out and nicely resolved (and yet, as in real life, the prejudice itself is not so easy to dismiss). Anyway, there's another great review of the book over at Wands and Worlds that makes these and all the other points I was going to make, so how about you just go and read that?
Northlander can easily stand on its own as a story, but I am very glad that it is labelled "Book One" and therefore I may someday look forward to reading more about Ellin, her friends, and the fascinating world of the Borderlands. In the meantime, Northlander has been short-listed for the Cybils (yay!) and I hope that it goes on to gets all the attention and praise that it deserves. Well done, megburden!