I knew about Kohan from some local game reviewers' reviews of this game. I had tried it out and was pleased with this game.
Kohan perhaps is the first fantasy RTS to properly implement squad-based units, supply zones, garrisons and several other game features which would not have been out of place in games like the first few Close Combat games. But unlike those painfully micro-management-heavy games, Kohan is substantially more accessible, though that's not saying that players can approach this game like it's Warcraft.
The squad-based unit system, and its intricacies like morale, flanks and such really puts some depth into battles, along with the variety of units with different strengths and weaknesses. With the exception of some story-based enemy units (like the heinously difficult Shadow Lords) and hostile 'critters' (such as some painfully powerful Basilisks), the game's roster of units felt quite balanced.
Kohan's city and outpost building features very much prevents players from adopting stalemate-prone defensive strategies, while its map designs provide players opportunities for flanking and the likes, with the exception of some story mode maps that are linear. Also, with the drain on resources that some buildings cause, it encourages players to think ahead and not make management blunders.
The story is not exactly original, of course. It's yet another good-versus-evil fantasy tripe. The only notable difference from the usual stereotypical fantasy lores is the inclusion of the Kohan, the titular immortal sovereigns. These persons function a lot like hero characters, except that they are virtually impossible to permanently put down. Nurturing them to their full Ascendant levels is quite fun, and players would certainly feel powerful with a bunch of them on their side.
Kohan's graphics is nothing much to shout about. There were mediocre, at worst, and there are clearly some repeated unit models for certain types of troops available to all factions, namely the Engineer. Sound is also quite mediocre actually, especially after having been treated to the relatively more lush graphics and more fantastic audio in other fantasy strategy games, namely the Heroes of Might & Magic series.
Fortunately, sounds and graphics really play second fiddle to the strongest point of the game - its gameplay.
Overall, Kohan is definitely a more than worthy rental, and would make a nice addition to the collection of anyone who loves fantasy strategy games.