In Civilization series I have played only the original. Repeatedly. One more turn... I have tried FreeCiv and I remember game mechanics are identical. But is it different otherwise? Is AI more intelligent without resorting to cheating?
I immensely enjoyed Colonization and in my opinion is better game than Civiliztion itself. It has more micromanagement, but it is manageable: I particularly liked more detailed trade system and colonists having professions (I can recall lumberjack and soldier). Something like turn-based Settlers with Civilization's user interface and game mechanics. So tobacco is cultivated, it is processed to cigarettes, and cigarettes are sold for good money. More cigarettes to sell if civs responsible for tobacco farming & cigarette manufacture are trained professionals in their respective jobs. To me it was really impressive back in the day and had just the right amount of detail without going too much micromanagement.
Civilization V has got quite bit of flak in this forum. But I just read this from TVtropes:
Can you name me Civ-like game where AI is equally considerate and game allows stacking?Know When to Fold 'Em: In contrast to the incredibly stubborn AI of past games (IV in particular), the AI in V won't hesitate to surrender if things are going particularly badly for them. It's even smart enough to change its mind about whether or not to declare war on you. If you spy an army approaching your border and get warned by a spy that Genghis Khan is planning an invasion, marching your own army up to the border can actually make the AI reconsider and pull back.