I listened to it on a long drive recently, and really enjoyed the audiobook version. The voice actor did a good job, and I liked the chords with the alien voice. The last 20% we were listening on the edge of our seats.
And then, a few weeks later, it's... fine. I like to call books like this "Good Time Fun". It probably won't be remembered in 100 years like other more timeless works, but it's a heck of a lot of fun if you just go along for the ride.
Another commenter suggested Young Adult, and that's exactly what it feels like. There's challenges, strong emotions, a bit of a a twist or two (pretty easy to see coming), clever creativity, Science To The Rescue, and Friendship Conquers Everything! You know, Good Time Fun!