Not as good as Advance Wars, but almost. The most important differences:
- There is one new unit, but it does not add much to the game since the original set of units already was perfect.
- The COs now usually have 2 special powers, and thus their balance is a little better.
- The missions actually provide some new types of challenges, but usually through restricting the movement of the player.
- The missions are significantly easier, especially those of the hard campaign.
If you've played Advance Wars, Advance Wars 2 will feel like an addon with easy missions.
If you haven't played it and you're an experienced strategy gamer, go for the original. If your not too experienced with strategy games, go for part 2.