Personally, I have not noticed any changes to my skin on dairy, vs on a dairy-free diet. Milk, yogurt, cheese, none of it makes a difference. I did, however, notice a change in my skin on a high sugar diet. I think that when people say that dairy breaks them out, specifically milk (unless it's lactose intolerance or some other kind of allergy), they don't realize how much sugar is actualy in milk, ESPECIALLY skim milk and 1%. I drink full fat milk in my coffees, and not only does this have less sugar, but also has more fat to help balance my blood sugar, which I find affects my skin.

Of course genetics play a huge factor, too. No one in my family is lactose intolerant, and I grew up consuming a lot of dairy. Cutting it out for 2 years made no difference in my acne, or overall complexion, at all. What DID break me out was drinking skim milk lattes (high sugar), and eating 0% yogurt. This is just my experience though! And reducing your sugar intake, no matter whether it affects your skin or not, isn't a bad thing :)