I have two KWPN horses. A Flemmingh and a Vivaldi. Both very sharp, active horses. Bred to work hard and do higher level dressage. Put a novice on these horses.... that's asking for trouble. Dutch Warmbloods are mostly bred for professionals. Pro's want horses that are forward going and very hot.
Allthough my KWPN's are the most lovable horses when I'm nit riding them. Very sweet!
I love my 16hh Dutch Warmblood mare. She's out of Ruben O. Four Seasons is absolutely right, though. You HAVE to treat these horses as your second or first job. I ride mine every business day unless storming, in which case I ride her on the weekend. I longe her and then ride her. I start with trotting lots and lots to establish collection and control before even thinking about a canter. I'm perfectly ok with that however, she is such a beautiful and smooth trotter. Then after she is supple at the walk, trot, and canter I then jump her. She makes jumps feel like we're cantering poles on the ground! She's the smoothest jump I've ever ridden. And I've jumped a lot of horses. In my opinion, a horse is a horse, and if you want a good mount, you better be working everyday you can to achieve that with your horse. I am a big fan of Dutch Warmbloods so far though.