It's good to read the three major books on the case in addition to the available police reports and police interviews with the Ramseys in order to come to one's own informed opinion on the case.
I think James Kolar had his heart in the right place but I don't think his book is a good analysis of what likely happened in this case. There are several important factual inaccuracies and misleading reports in the book as well as major leaps of logic and a large omission of relevant facts and arguments that were put forward by Steve Thomas and others. I plan on writing and sharing a detailed review of the book in which I'll analyze the arguments and evidence that Kolar puts forward and I'll compare it with the evidence and arguments that Thomas puts forward in his book. There is a clear difference in their style of reasoning and reporting of evidence.
In my opinion, Kolar's book has really damaged the case by dividing the camp of people who understand that the Ramseys are obviously involved in a cover-up into separate camps in which JonBenét's murder is framed as a whodunnit mystery as if equally valid and strong arguments can be made for either of the three Ramseys. I think this is clearly not true and has helped take attention away from the person most implicated in JonBenét's death by evidence: Patsy Ramsey.
That said, Kolar did have access to many materials that the public doesn't have access to and his book does contain several interesting tidbits of information that can be found nowhere else so it's still recommended reading. But don't think his suggestive style of reasoning brings you closer to the truth.