Their ads look great don't they? But I am convinced these are only better for you in certain circumstances - using the pro-active milk instead of full-fat milk, for example. Semi-skimmed or skimmed will also be beneficial.
Have a read of this:
http://www.theecologist.org/archive_detail.asp ?content_id=859
Particularly the bit that states it is more beneficial to eat a healthy diet and increase exercise. Also the highly processed nature of the foodstuffs, which is never a good thing.
If it worked so well, doctors would recommend it and even prescribe it, or a generic similar.