Worth full cost, if you understand and appreciate what you're getting. Less complex (also less pretty) than Imperator: Rome, but still has a lot going on under the hood. Pretty elegant strategic gameplay, though I haven't had to try to manage a large nation yet. Easy to burn through a lot of turns. UI could still stand some tweaking, particularly on the after-turn reports which are functional but rather a mess. Quite a different game from Aggressors (also quite a lot larger), not as large or overwhelming as Imperator. Being able to export battles to FoG2 (no DLC needed) is definitely a plus. Being able to migrate worker groups from area to area would be handy.
If you like the idea of managing ancient nations in the pre-Imperial time, out to western India, whether well-established or from the dirt up, and you don't want a more civ-type game (which is Aggressors, also worth buying but with quite different gameplay), without going insane managing families and all the glorious minutia of Imperator, then buy with confidence.