Originally posted by kcwong
Yes... when I have the resource I'll build it. Though it is not a "Must build. Or I'll die" type of Wonder.
For me it's one of the "Must build" wonders. I seldom wage much war early in the game, and therefore only have a few barracks when Sun Tsu comes around.
2. IIRC it makes barracks maintainence-free. Also you should sell all your barracks in the turn before AOW is finished.
You are correct that it makes all barracks maintainance-free, but you can sell the previously-built barracks after you get Sun Tsu. If you right-click on a barracks symbol in the city view you will get the "sell" option if that city has pre-built barracks. If you sell it, you get some gold, but retain the barracks due to Sun Tzu.
It may be wise to sell them the turn before, when it is easier to see the cities whith sellable barracks though.
The same applies to granaries and the pyramid btw. You can still sell off granaries after you built the pyramid.