I drink 2 cups of it before bed every night, OP. And no, there is not nearly enough caffeine in it to disrupt sleep whatsoever.
It tastes great with no need to add milk or sugar so it's practically calorie-free, and it has antioxidants and is just all-around relaxing to drink.
I love the shit. Hell, most fatasses could lose weight simply by replacing the soda and coffee they drink with green tea. Or, hell, any kind of tea for that matter.