I just finished the campaign. I agree that it ended very quickly, but it was satisfying enough all the way through. The Empire kept attacking me with large fleets between missions, so I got to have a lot of fun space action.
I was expecting FoC to be terrible and I was expecting to hate the Consortium, but I was pleasantly surprised for both. I'll still only play as the Empire, but the Consortium campaign was definately enjoyably playable.
EDIT: It terms of gameplay and continuity, the expansion is far far superior to the original.