Disclaimer: I enjoy the Paradox titles. I've played several of them: EU2, HOI, Victoria, HOI2, and HOI2: Doomsday. And, of course, CK (Crusader Kings).

Paradox isn't known for friendly UIs, CK is no different. But, you do become acquainted with it soon enough.

CK will not be for everyone. I believe one reason for this is because there are significant amounts of time where the player is just waiting for things to happen, such as changes in another kingdom's inheritance line or inheritance rules. Of course, war is always dynamic. I do like how troop strength is recruited in-game, during times of war - then back to the fields when peace returns. I feel research is handled well, through cultural diffusion. Although you are actively researching advancements, you can randomly receive technology through cultural diffusion. You also have to manage those uppity nobles and pesky peasants, as well as the church.

My problem is I'm too impatient. If you don't play as a king, then mustering the forces to take on other Dukes & Counts can be risky, because their leiges almost always come to their defense. Ouch! Patience is a virtue in this game.

Those new to Paradox titles should know that when loading a save game, you need to choose the save then click on your realm in the selection menu. For instance, if you've been playing as the Duchy of Apulia for several in-game years and save. The next time you load that save, you must choose it, then again click on Duchy of Apulia - again. Just like when you start up a new game. I believe this is not required in a couple of the Paradox titles.

As to manuals, forget it. Only the HOI2 and HOI2: Doomsday manuals are worth their salt. That's because Paradox had a fan create them. But, you can get excellent advice on the Paradox forums and more mac-specific feedback at Virtual Programming's forum.

FPS fans beware! :-) This is a thinking man's game! :D