This is a worthy expansion for RTW its really hard ( even if your a tribe) which is great for RTW veterans.
the huge battles look as great as ever and the campaign will be very very hard to beat ( especially as Rome)
The AI has improved very well in combat as well as in the campaign map and diplomacy is more reasonable.
there is a wide variation of troops and your strategy has to be completely re modeled than your strategy in Rome Total War.
new features such as Shield Wall and Horde give more exitement to the barbarian tribes and strikes fear of you decide to be any of the Roman Factions, and you have to look out for the invaders from the east
the hardest faction to play as in my opinion is the western Roman empire since the have many of the germanic tribes along their borders and tribes from Britain to start bombarding your settlements over there.
and the Western Roman Empire has probably the longest Border line and not enough troops to defend against the countless enemy troops looking to loot all of their cities
i really recommend getting this if you love Rome Total War