Excellent continuation
The expansion introduces a new really strong, slightly slow faction, but of a tremendous power. In addition it introduces new units that still the already existing ones complete more and unifies the human faction in the alone one with Gondor and united Rohan. It looks like to me a good idea since in the initial game Rohan he was remaining a bit unbalanced by that, though it had the best cavalry of the game, he was suffering from an infantry and a few decent archers, this is compensated by the soldiers of Gondor's infantry (with even more powerful new units) and by the excellent archers of the forest.
The game continues supporting the same virtues that the first one, a very good campaign and a few rapid items that become very pleasant, but also the same faults, the way of game in the strategic map continues being a bit sluggish, for what since I do not give a distinction to the first one.