I  found much better control of doneness and crustiness doing elbow mac mix with cheese sauce, than baking the whole thing in the oven. Also, I found that reheating this mac and  cheese is a lot better than the bake ones. If you like a crust on top, you can always put that in the oven with the boiler on to acheive that. I am sure both ways it is delicious, and it is a matter of preference.