The game does not offer an option for in-game management yet (although this is planned for later versions), but it has the option to watch any game. This in-game view, called PSPN Cast, creates probably the most exciting moments in the game, especially if you make it to the World Series.
What sets this game apart from most competitors is the fact that it relies on fictional players who are randomly generated every time you start a game, and the algorithms for this are very good. Although the players' names don't mean much to you in the beginning, it only takes a short time until you know your future hall of famers, and this is a large part of the fun, actually. There is also an option to import real players (from the Lahman database), but PureSim really excels when played in fictional mode. So if you use this, don't expect realistic numbers.
The second original idea is the introduction of scouting: you'll never see a player's actual rating, only your scout's view of them. Needless to say that some scouts are better than others, so that your number one prospect might turn out to be a career minor leaguer. This makes statistics very important, as they sometimes measure a player's skill better than ratings.
Overall, PureSim is highly recommended, as replayability is virtually endless. If you are a baseball fan and you like stat-based games, you should definitely give this one a try.