I have played Rome II as well. Really great game. I am yet to try Troy...
I am a big fan of that game as well. I recently played the Wrath of Sparta DLC.
I was also big on Empire: Total War, I enjoyed the naval battles, playing as the British.
A big improvement that Troy made was more fluid game play with the User Interface. I am still trying to learn the ropes of the game though.
Oddly, Troy is currently only available on the platform, Epic games. Which is a free to install gaming platform like Steam.