Though it is steeped in social combustibility, 'Sweat' often feels too conscientiously assembled, a point-counterpoint presentation in which every disaffected voice is allowed its how-I-got-this-way monologue. And this thoughtful, careful play only seldom acquires the distance-erasing passion of Ms. Nottage's 'Ruined,' the 2009 Pulitzer Prize winner about female casualties of the Congolese civil war...'Sweat' is best at its muddiest, when love and hate, and the urges to strike out and to comfort, teeter in precipitous balance. That's when Ms. Nottage's characters, and the cast members who embody them, emerge in their full tragic humanity.