We had a medieval show with Freisians and Percherons. The Friesians were flat out crazy. They were flighty, difficult to deal with. Their canter is horrible - it's a really rocking sort of one so you've got to have a really good seat to ride it through. I thought it was just the one but they were all like that.
I'd never own one. But, they are really nice to watch. I'd recommend anyone that wants one to go ride one first and spend time around them, it might very well change your mind. There are a lot of people that like that kind of horse, but not me!
Unless it weighs a ton... it's just a horse. Draft horse motto.