I think that it is healthier because there is not as much extra stuff in the milk. Plus, anyone can have it. Unlike regular milk,people who are lactose and tolerant can't have it. I drink my parents milk all the time and I don't get sick. Plus it tastes way better than regular.
If you're not lactose intolerant, lactose-free milk is no more healthy than regular milk. They are both quite nutritious and healthy. The lactose in regular milk poses no problems to your body, because your digestive system can break it down just fine. The lactose is just another nutrient.
If you ARE lactose intolerant, then of course lactose-free milk is healthier, because it doesn't trigger the negative reactions that regular milk does.