I wish it were possible to give half stars. This was really a 3.5 for me. I enjoyed the story and read it all in one sitting, but somehow it left me frustrated. The characters all felt like themselves and yet unrealistic at the same time. 
 (Spoilers ahead if you have not seen the movie...) 
 1) Veronica gets sucked back in-that makes sense, but then she doesn't use her law degree at all? It felt like the author created this concept where there are only the two extremes. Either she's a corporate lawyer in NYC or she is a private detective in Neptune. Real life uses more of a sliding scale. (e.x. criminal defense attorney who does her own investigations...) 
 2) Mac leaves Kane Software to work for Veronica full time? Both of them should know that Mac's expertise is only needed on special cases. I would have expected Mac to keep the high paying job, and help Veronica in her free time. (Mac's character was always interested in making money: in TV series creates purity test to buy new car; in movie states took Kane job because of the salary) 
 3)All three of them (Veronica, Wallace, and Mac) absolutely did not enjoy Neptune in high school, the chances of all three staying seem to defy logic. 
 That being said, while the larger life choices seemed out of character, most of the smaller actions, the dialogue, the day to day decisions felt very authentic to the original characters. 
 tl;dr Good, not great, question the authenticity of life choices