I'm by no means a Civ expert, but Civ 4 is a well-balanced game: It's way more fast-paced than Civ 3 and 6 (at least to me), and it the AI offers just enough help with suggestions to keep the game rolling rather than interupting the flow. I also appreciate how you can win the game diplomatically. You can peacefully without having to nuke other nations. Overall, a lot of fun to play and well-designed!