SoZ trumps KT all the time. 1) SoZ is cheaper (but then it's half an era earlier, so what do you expect?) 2) ACs are better units than Crusaders: the extra hit point & movement far outweighs the 5-3-1 stats. 3) KT expires way too quickly for my liking. I would never pre-build it, in fact I don't even look at building wonders from scratch until Copernicus [except in 20K games of course, then KT is a fantastic addition if you can squeeze it in]. So by the time it's done, I'd get probably 5 or 6 Crusaders before hitting Steam Power anyway. The only thing Crusaders are good for, IMHO, is disbanding for 17 shields to allow first-turn rushing of Factories and Coal Plants at normal cost rather than double cost.