BAR is quite a complex and detailed tactical simulation, with much emphasis on formations and morale. Unless you have a strong interest in the period, especially at the tactical level, you might the amount of detail a bit overwhelming. On the other hand, if you do have that interest, then BAR is the definitive treatment of 18th century combat.
In terms of gameplay, is a game session more process than choice? How would you say it compares to MPBS in terms of gameplay(not complexity)?