Been playing Civ3 a while, and only just started with 4 (both Warlords and BtS)
Is there anything drastically different regarding strategies between the two? Replacing att/def values with single strength on units seems a little confusing to me.
Definitely read the articles in the War Academy. I had been playing Civ3 for a while last year, and picked up Civ4 again this spring. First game was a disaster!
1. Don't expand too fast, as other posts have said. 8 cities by 0AD is OK on lower difficulty levels. Each city *costs* you maintenance, until it grows. Roads don't help either.
2. For combat, archers are the opposite of what they were in Civ3. They were offense in Civ3, and they are now the preferred city defenders. Axes and swords are better offense in Civ4 ancient times, especially with CityRaider promotions. Be sure to read up on promotions.
3. Most important combat difference is the change to siege weapons. In Civ3, they were defenseless, and could only bombard. In Civ4, they can attack and defend, but the key difference is the overall strategy for their use. Two words: collateral damage. One builds a lot of siege (say, almost as many catapults as axes) and uses them to wear down the city defenders. Literally, suicide siege. As each catapult kills itself attacking the city, it does some damage to all (or nearly all) of the defenders. Your attackers have a much easier time conquering. This tactic continues with trebuchets, cannons, and even artillery.
4. Rock-paper-scissors. The units in Civ4 are nicely matched; each is effective against certain kinds of units, and vulnerable to others. You will want a mixture of attackers (say, 50-60%) siege (30-40% and stack defenders (rest) in your stacks.
5. Overall, you will make war less often than in Civ3. It is possible to get along well, and mutually beneficially, with some other tribes -- esp. if you share a religion. Until you know what you're doing, waging war too often can leave you behind in techs.
