There is no straight answer, the most I can tell you is if my budget allowed, I'll not hesitate to pay for the difference.
I'll illustrate the "value" represented by the price difference with the following scenario:
If you are fairly new to the hobby, or if you want to try things out and explore your direction in this hobby, go for D200 because you sure can have a good start in this hobby with D200, and let you try a lot of options at good quality benchmark.
If you know what you are looking for, wanted something to feel your need, and put quality ahead of C/P, then go for DA8, it delivers, and you can keep it for a very long time, even in system compromise of several flagship headphones.
If you are budget minded, always prefer bang for the buck, will study a menu carefully when you enter a new restaurant looking for the best deal of the night, then you won't regret to take the D200 anytime.
If you appreciate quality, look into how things are delivered instead of comparing features and specification, will consider the catch of day instead of the "regulars" in a restaurant, then you should give DA8 a try, it might not be everyone's choice, but you'll happy with your pick after you spend time with it.
Edited by Andykong - 5/3/14 at 7:05am