I have been enjoying the game a lot since getting it. The graphics are awesome but my comp is a lil dated so I scaled things down to make things run smoothly.
Battles are awesome, just like what made the original great. Unit details are on the money with each unit having their own distinctions. The battle options are far more streamlined and accessible; just like the rest of the game on a whole really. You can access all the premade army formations for your units and enact them with a simple click so you no longer have to set formation for each unit yourself. Same goes for special unit orders as well.
The fighting is pretty sweet to watch unfold on the battlefield. You can zoom up nice and close and watch our peons fight an army of rebellious slaves or new tribes. The AI can be pretty smart using baiting tactics to lure your main forces into an ambush or within range of siege artillery; especially when you're fighting equal or stronger factions.
You can no longer have unlimited numbers of generals or unled army troops. In order to raise an army you have to 'raise forces' which requires the hiring of a general with random starting traits, who can recruit units for his army. A general and their army have a max # of units but as they gain more experience through fighting the army gains traits and can unlock more traits that provide bonuses army wide. In addition your general also gets exp for skills as well.
You can hire agents as well: spies, gladiators and diplomats. They level up and work the same way pretty much as the other games.
So far I have been playing as Rome with the Junii with hard difficulty settings. Game is difficult and enraging sometimes depending on the consequences of your actions but very rewarding and fun when you take over the settlements or win ambushes.
Two main skill trees: Military and Civic. Again similar to previous Total War games.
As the game progresses further, I find the game begins to get more sluggish and slow. Hopefully they will fix that soon with a patch. Nothing that ruins the game for me, but makes each turn take longer.