An interesting game to say first; I picked it up during the Publisher Sales and found it intriguing enough to buy
The pros and cons.
Fairly easy controls
Historical accuracy maintained (somewhat) closely
Complex system to navigate as it grows, demands full attention
If you've played Age of Empires, the similarity between these two games begins and ends with them being RTS games.
In Knights of Honor, you can not simply attack as you please, you have to build relationships, maintain funds, supplies and even the happiness of your own people to prevent revolts. It can really test patience and strategy.
However, the characters can be interesting and the combat is fairly simple, controlling entire armies with relative ease rather than trying to manipulate small groups of soliders like in Age of Empires.
If you haven't tried any RTS (real time strategy) games before, maybe wait on getting Knights of Honor or buy it on sale but if you love RTS games like this, Age of Empires, Rise of Nations, Civilization, then give Knights of Honor a try.