I've only cast both of these rods on several occasions, about 15 minutes with each rod each time.
That said, I would get the CND because of its much crisper action and fast recovery from casting load. It is not a fast rod like the T&T's, GLX's, Loop Green Series, or Meiser fast-orgressive rods; however, it is a very nice medium action rod with a good amount of power.
I find the Scott ARC 1509 to be a somewhat slow rod, not as slow as a Sage 9140-4; but certainly slower than a medium action rod. I also find it to be more of an 8 wt than a 9 wt as Sinktip has.
Also, when I cast the Scott with the use of both hands to load to rod (as is my normal 2-hand casting style), the Scott folds up and doesn't like it at all. The CND doesn't complain and handles the double-hand loading motion.
If it were my money and I had to chose only between these two, I chose the CND. However, because I have other choices, I would forgoe both of them and get one of the fast rod with the T&T 1409 being my favorite with Meiser's 13'6" 8/9 a close second.