Pretty realistic if you're willing to climb the steep learning curve.
The game is most enjoyable when you're playing another live opponent. It's virtually impossible to guess what your opponent is doing, so there's lots of room for deception, just like real baseball.
Finally, the voice-over audio does a great job of putting you into the action. The announcer has good commentary that's non-repititious and informative. My personal preference would be if it wasn't presented as a "stadium" announcer but instead as a play-by-play radio voice, but that's splitting hairs.
A very worthwhile family-friendly game.