IMO its the best tw game out there. its jst the right difficulty, and battles can be a real bitch if you don't have a big advantage.

the hardest part? probably techs, naval, and balancing economy. the economy post-patch 1.2 is hard to keep up due to high upkeep costs, and the naval aspects of the game are extremely difficult with non-naval factions like Russi, the Marathas, Austria and Prussia.

easiest part? probably the fact that the enemy never sends a serious invasion force into your lands. though ive started to have this happen more, they are mostly just single units of militia or groups of weak units/cavalry.