I read this aloud to my sons (13 and 11) a bit each night. None of us liked it as good as the first one in the series (which I gave 4 stars), though my 11-year old would grant it 3.5 stars. It's also worth noting that both of them liked it enough to want to continue with the third title. 
 Most of the characters from the first one make an appearance here, and you'll also meet some new ones. Gregor now has a new quest, and though he is reluctant to delve back into the Underland and all that entails, he does what he has to do. 
 There was a part of his quest that I did not expect, and that helped with the storyline somewhat. Things get dull when they are too predictable. Still, Collins knows how to write a story in a way that makes it easy to read through even the parts you aren't enjoying that much. The hope of something else really cool about to happen keeps you reading, and that's fine. 
 The stuff I didn't like: 
 (view spoiler)[ What most annoyed me this time around (and is worth at least -.5 or more) was Gregor's continual ruminating about Boots about 3/4 thru. I get it, I understand it, but I still thought it went on too long. 
 I welcomed the mild budding attraction between Gregor and Luxa, though I think my boys found it eye-rolling. 
 I also found Gregor to have more attitude in this book, and who needs that?? (hide spoiler)] 
 I'm hoping the third one is better!