I really like my Quarter K. I got one of the British Open fundraiser discs when they first came out and still throw that disc. I don't remember when that was, but if you do, you know how old the disc is.
While this is not the disc that was hyped (1/4 kilometer distance), it has become a very useful disc. For me, this disc is goes about as far as a Beast/Flash/Orc, but is much more predictable.
Durability. As I said before, I've been throwing the same QK for several months and while it has some dents and dings, still flys predictable (very much so on hyzer routes) I've hit plenty of objects with this disc including rocks, trees and pavement,
but do not abuse it. (If it is a heavily wooded hole, I probably won't throw it.)
Back to the original post, I would agree. The QK and Wraith are not really the same type of disc. I think the Wraith is going to become the start of a new category of drivers. Like the Aero, Cyclone, Viper, and Valk are in their respective categories.