First, I've been told that the horns that BD plays on are exclusive to them and impossible to buy.
Now, that said, I've played on Dynasty and played around with the Yamaha. I greatly preferred the Yamaha. Which in 2005 is going large-bore as standard.
The 2005 Dynasty euphs are adding 4 oz to the back of the horns balancing them so much better then the 2004 line.
In all honesty, I would go with the Yamaha, I liked the tone I got out of it, I liked the responsiveness and I wasn't even warmed-up.