I think if it is between the 2 breeds a DWB would satisfy both jumping and dressage disciplines. I posted a bit ago about wanting one two if you look there I was given a lot of good advice, though I would ignore post 2.
In my research I saw photos of friesians being jumped but also read that because of their heavy gait and feet they are prone to bone chips and Pastern problems. I don't own one yet so can't be sure but that is what I read. I would hate for you to limit your riding because of your horses breed, if you like jumping and dressage you should get a horse that can do both with ease.
Or get a cross breed
"It's a lot like nuts and bolts - if the rider's nuts, the horse bolts!" ~Nicholas Evans
Last edited by horsplay; 01-26-2011 at 06:13 PM.
Reason: added some