Bumped a generous three stars, mostly because it left me intrigued (though not officially eager) for the sequel. Honestly, I don't recall how Bumped ended, but nothing about Thumped is particularly compelling or interesting. Reading Thumped, I'm left stumped as to what about Bumped led to me pick up the sequel.
I will say this much: the writing in Thumped isn't as wrenched as I recall it being in Bumped. Perhaps I'm just more used to McCafferty's narrative style, but I'm tempted to say Thumped is genuinely a better written book. Unfortunately, it's much, much thinner on plot. There really isn't much to Thumped at all. That being said, I actually wish the final act of the book hadn't been so ambitious. A lot happens in the last several chapters, but it's all very uninspired, obvious, and banally moralistic. It strains for profundity, but feels very tired.