I've tried both sides of the spectrum ranging from drinking no milk at all to drinking 2 gallons of milk per day, and I've found that drinking no milk works best for me. Milk got me fat, gave me horrible acne, bad breath, made me bloated and smooth, and increased estrogen levels. I'd possibly even attribute my pubertal gyno to milk because I drank at least a gallon a day during my youth.
Although the lactose (that's the carbohydrate in milk) does not register very high on the glycemic index, milk itself has something about it that makes it very high on the insulin index, almost as a high as sugar, and the insulin index a much better indicator of how much something will affect your insulin levels. GOMAD will have to be drank throughout the day, and spreading it out that much will have your insulin levels spiked constantly throughout the day, leading to insulin insensitivity and possibly even type II diabetes. I always bulk with fruits and whole wheat/oat products for my carb sources (with the exception of maltodextrin and dextrose periworkout), and it works very well to keep me lean while gaining maximal muscle.
Furthermore, milk comes from cows that are pregnant year-round so that they may produce the maximum amount of milk possible, but this also leaves them with very high estrogen levels. I have had blood tests that proved, at least in my body, that milk highly raises my estrogen levels. Again, I was drinking at least a gallon a day since before I was even a teenager, and I think that this may have contributed to my pubertal gyno as well as my acne.
Nowhere on my body didn't have at least a pimple or two on it. Neck, back, face, neck, chest, arms, forearms, glutes, legs, and even one or two on my calves. The blackheads were gross, too. I could spend hours pinching the hardened plague-ish stuff out of my shoulders, face and chest every day. It all went away almost completely when I stopped milk. The bloatedness and smoothness aren't that fun either, so I'm pretty against milk.
Milk is my favorite drink in the world, don't get me wrong, but it's just not worth it in my opinion or even effective. There are so many better options that can out-do milk. And don't give me that crap about not being able to eat enough solid food, so you're drinking milk to meet your caloric needs. I am eating 6k calories per day, and it's almost all solid food with the exception of a few protein shakes with no weight gainer.
To each his own, but I'm not doing it, and I wouldn't recommend it to anyone either (obviously haha).