That depends on your definition of coffee.
It's a Nescafe (known as Nescacrap) blend.
My mom is a die hard gotta have a cup of coffee in the morning. Her opinion was "It's drinkable, I've had worse".
I drink some coffee, preferable with ice and splenda and non fat milk, but I will have a cup in the morning hot, and I wouldn't touch coffee in WDW with a ten foot pole and two pounds of splenda. I couldn't doctor it enough to make it palatable.
They serve the same stuff in the food courts and resturants. My mom said it was worse in the food courts but drinkable at our TS breakfasts and TS dinners. I would guess that the food court coffee had sat around and the room and TS was fresher.