It would be rather pointless to provide a detailed review of this book, as you will either be intrigued by it (i.e. comic book or superhero fans) or have no time for it.
As a life-long fan of Superman (and thus The Flash if only by his association with Supes) in all media outlets, I found that the most interesting aspect of reading this book was seeing how the comic themes evolved over time.
In the first couple of stories, during what I consider to be the light-hearted comic book years (I'm not too good with all the different comic book "Ages"), the emphasis is placed not on the "Big Race" itself, but on what it is for or what happens along the way. Usually, the race is either run for charity or to keep Metropolis/Central City from being destroyed. Along the way, Superman/Flash run into obstacles that would allow the other to take a clear victory, but each helps out his fellow man. By the end of the race, the "world crisis" is averted and both superheroes cross the tape (rather predictably) in a tie.
In the later, more serious stories, though, more competitive nature is shown by each hero. While the base story is the same (race to save the world from evil-doers), there is much more subtext given to how badly each hero wants to win the race. Though altruism always prevails, it is clear to see that it is much more difficult for the "modern" Supes/Flash than for their comic predecessors.
So, if you are a Superman/Flash fan, or just like comic books in general, this compilation will intrigue you. Plus, if you are a history buff like myself, you will find it interesting to observe how the definition/actions of superheroes change throughout the decades.