I MUCH prefer Hand Breeding than Pasture Breeding. There is NO control with Pasture breeding, plus unless you have 24/7 watch, you really do not know when your mare was covered, and when she should be due. With a well run breeding program, dates are very important. I couldn't imagine not having a clue as to when my mares were due. Exposed from this date to this date is not enough. I need to know, "She is due on THIS day." Whether or not she foals on that date, which they usually don't, but it gives you a better idea of when to set up camp for FW.
As for control, there are too many "what ifs" to make me want to try it. What if she kicks him? If my stallion is worthy to breed, and people would want to breed thier mares to him, why am I going to risk one mare kicking him. What if he hurts her? What one of them is run through a fence or they hit a slick spot and get hurt in some fasion? What if he doesn't cover her in the time I have them together? What if what if what if?
What if I want to start hand breeding, and all he knows is pasture breeding? There is a BIG chance you will have no manners, no respect, no control, and things have a high probability of not going to go as smoothly.
When doing live cover, you need to be responsible and aware of your mare's readiness. It all comes down to your knowledge and experience. You have to take the time to tease, and watch, and KNOW the signs.
Pasture breeding is very outdated, and most people that do it, do not have the experience to safely Hand breed.
AI is best in many situations, but with some breeds/stallions, it is not applicable. Thoroughbreds have to have live cover. And in some cases, stallions cannot be collected. Our older stallion is like that. He is 28, and cannot be collected.
In his case, he could never be pasture bred either. I would never risk him. I doubt I would ever risk intentional pasture breeding.
We do both Hand Breeding and AI.