While I think the princess series might be better books, this series has a special place in my heart, and I have a special gold star for this second installment.
You know how in a lot of fantasy trilogies, the middle book is less a book and more just a bridge to get from that awesome initial idea that got them the book deal in the first place to the huge third-installment payoff? That doesn't happen there. As weird as it is to have to highlight this, Goblin Hero is a real, actual, full story with its own arc, new characters who get their own arc, and impacts that are more than just setup for the next installment.
I know a lot of people who have said the first book is better, tighter, funnier, and maybe they're right, but I like this one better than the first in a lot of ways - not the least because I find the side characters less (intentionally) insufferable. We get a few more rounded-out goblin characters, even a hobgoblin, and in a massive improvement from the first book's most glaring deficiency, a lot more ladies.
Of these, my favorite is Grell, the wise (or maybe just old and impatient) goblin who's spent more time than anyone should have to taking care of baby goblins and really wants a change. She might be my favorite wise old mentor character because while she does, in many ways, serve the function she is quite clearly her own person doing what she does for her own reasons. She's clever, smart and not above doling out the smacks when smacks are warranted (or the help when that's needed too).
But we also get Veka, a goblin who gets it into her head to be a wizard, Braf, who appears to be a big lummox of a goblin, and Slash (sorry dude) who's probably more competent than most of the cast, but hampered by a small weakness. I really liked them all, and for me, the best parts of the book were this core of characters interacting with one another, no matter what they were doing.
While this book isn't a clear sendup of any particular type of fantasy or adventure (to me, it seemed to actually have the most in common, in terms of pacing and tone, with some of the less romance-oriented urban fantasy) it's still got plenty of key tropes fantasy fans will recognize and hopefully be amused by. Overall, an enjoyable book.