I'm running a Black Company campaign right now. It's a lot of fun. The magic system isn't that bad once you get used to it though I should warn you it can be pretty easy to break. Last session I had a Rokes Drift style battle planned where the PC's would be leading the defence of a manor filled with wounded soldiers from a large number of well equipped enemies. Now one of my quirks as a DM is that I normally roll dice in the open. Anyhow the mage combined the create energy acid with create water to create an acid fog a'la musterd gas. The enemy were unaware that the PC's were in the manor so he got a surprise round off on them. Damage was fairly low, only 3 or 4 points but since it was a surprise it forced a fort save... I rolled for the grunts as a group and the save came up a 2 and almost 15 4th level warriors dropped to zero HP in a single round. The sheer diversity of the BC spell system allows for amazing adaptability and if a player crunches the numbers right he can overpower just about anything you throw at him.