AFAIK, both the K3 and the DXG have the same Pearl screens (they look exactly the same
I personally enjoy reading regular books much more on the larger screen. It has more of a real page feel and it is more immersible to me.
The 6" screen feels a little like looking through a keyhole and the need to refresh much more frequently takes away from the please of reading a bit.
But, to each their own. I personally used to buy mostly hardcovers, while others are happy with mass market A Format paperbacks.