As I'm sure you've read in a dozen other reviews, this book is very derivative. I'm not going to get into all that, since most literature these days is derivative to some degree. The story is familiar enough and enjoyable enough that I did get the second volume in the series to see if it improves and how the story progresses. I'm not very far into the second book, but so far, it has the same issues for me that the first one had. That is, issues with things being exaggerated to make it sound impressive: 
 - A city with walls that are 100 feet tall and 30 feet thick? 
 - 12-foot-thick stone doors? 
 - Inch-thick metal plates on armor? 
 - A dead volcano that's 12 miles (or more) high? 
 - Lanterns at a tunnel entrance 2+ miles away that are easily seen? 
 - A crystal palace that's a mile in height? 
 - Icicles that are 100 feet thick? 
 Too often distances and sizes are overstated to make things seem impressive when, in fact, it makes your brain pause because it just doesn't make sense. A 12-mile high mountain is more than twice as tall as Mount Everest and practically reaches into SPACE; 100-foot-tall walls are the equivalent of an eight or nine-story building and would leave the majority of the city in shadow throughout most of the day; 12-foot-thick stone doors would have to weigh tons upon tons - what hinges would support them or what number of men could move them? A crystal palace that's a mile high sounds impressive until you consider that's FOUR TIMES the height of the Empire State Building, which has 100 floors, and said palace does not have escalators, elevators, or even, I dunno, teleportation pads? 
 I'm surprised a lot of it wasn't scaled back or toned down when the book was edited. And unfortunately, with everything spelled out so exactly (they covered X leagues, the river was a league across, etc), the math simply doesn't work out in virtually any situation. For many people, this might not matter, but for people whose brains like to play with numbers, it gets frustrating and distracting. A river that's 3 miles wide? Good grief, the Mississippi is only 1 mile wide at its widest point. And said river flows into a lake? How big is this lake? 
 Aside from all that, the only other really distracting thing is that he seems to forget it's winter every other page during the first half of the book. It's winter, it's really cold, there's almost six feet of snow on the ground in some places - so let's have the main characters get stuck in a rainstorm that drenches them to the skin. Because people who are soaked to the skin on the plains in the winter totally won't die from exposure. In fact, they'll fly up into the clouds on their dragon mounts, because it's bound to be much warmer up there...? 
 I really hate to nitpick other authors' work, but to be honest, these little mistakes are like having a scratch on an old 45 record (yes, I just dated myself there): you get into the flow of the music and then SKIP. Okay, that wasn't so SKIP. Ok, that's getting SKIP. Etc... 
 So, sorry Chris, but I hope this is something you either outgrow during this series or before you finish writing the next one.