I enjoyed the second book of the Hunger Games series much more than the first book, because, in my humble opinion, Collins used her storytelling powers far more effectively here than in the preceding book. I wasn't able to guess as much of the plotline as I expected to, judging from my experience with The Hunger Games #1.
Even the character of the plotline itself transformed. The relatively steady pace of book one turned into an unpredictable motley of events, in which one event broke off quickly into another without a significant transition 'phase' in book 2. That was a good thing, because notwithstanding that I would have probably lost interest in the Hunger Games series.