The campaign is good, and it has better online play than the first.
The gameplay uses the same solid mechanics of the first game. In each campaign you play as one of the 6 characters and manage their armies against the enemies armies for each battleground. In between battles you can usually upgrade your armies by learning new skills and buying new equipment for each battalion, as well as add new battalions to your army.
On the battlefield you control the leader in hand to hand combat. You can als 't macromanage all of your battalions on the battlefield. The difficulty is often knowing how much time to devote to each task. If you spend too much time commanding the battalions, you won't give yourself enough time to devote to going directly to the one that your leader controls so you can perform better than if you let the battational do battle by itself. On the other hand if you just spend all of your time hack and slashing your enemies with your leader you may do a lot of damage but allow the rest of your army to go down. For example archers are a lot less effective in certain situations, such as when an enemy engages them in hand to hand combat. If you allow them to stay in that situation you may win the battle you directly command but lose the operation because your archers and cavalry are left in hand to hand combat and die off.
One thing that I wish that the developers would have changed this time around was enemy leader visibility. The leaders often look too similar to the troops in their group, and the problem with that is that one of the fastest ways to destroy a battalion is to kill their leader. If you can't find them then what's the point? In my opinion it makes some battles a lot more difficult, in fact very difficult in many situations.
The graphics are about the same as the last one. Pretty good, and they definately do the job.
The sound aspect of the game is pretty good as well, although much of the dialogue seems very dumbed down, and isn't as good as you might like it.
$39.99 isn't a bad price for the game, but since it essentially the same as the first one except a different story and more online play, it is harder to call it a value considering the original sells for $19.99. If you haven't played the original, I recommend getting it first because of the lower price. But definately pick this one up after that, whether soon after or when it drops in price.