This is a nice RTS game, but i really prefer other styles, it's still a good game because...
I'm not saying it is a bad game its just that I prefer much more the RTS games where you collect resources in some way, then you build your base and your army and then comes the fighting. In this game you choose before the battle what units you want. Then comes the battle and the units you lose are gone and won't come back and because of this the battles are really short. That's something I didn't liked at first but after a while I started to enjoy the battles.
There are many types of battles, one that I like very much is the siege, where you choose to either defend or attack a Fortress.
There's also a mode in which you can buy units during the battle but it's not like you can build up an army, its more like a little reinforcements.
What I liked very much is that there can be duels between the heroes, where no other units can interfere.
I really liked the variety of units that it offers. Also the graphics are excellent as well as the sound effects.
I think that if you prefer RTS games of collecting resources such as AoE, AoM, Starcraft, warcraft, it is going to be a little difficult for you to get used to this type of game, so I would say you rent it or borrow it to someone and try it first.
If you like ALL RTS games then, yes it is a nice game with good graphics and a good story.