ChaosArbiter
King
Given the choice between KT and Sun-Tzu, I'll take Sun-Tzu. (Yes, obviously, I'd rather have both. Dare to dream.) Yes, your core cities should have barracks by the time you get Sun-Tzu. But at higher difficulties, it is really nice to have one-turn healing in every city.
Also, you won't have to pay for your Barracks once you get Sun-Tzu's. I prefer it, myself, though I play on Warlord, when the Computer is too stupid to use the units it gains from SoZ/KT effectively anyway. I don't go for many wonders anymore (yay! Off wonder-addiction!), but Sun-Tzu's is one I love, since I don't have to pay upkeep.