Having had only a brief play with my 8K due to medical reasons, I can safely say pixelation (or rather SDE) is a distant memory. Running TheBlu is an absolute eye-opener with the added resolution and FOV. Other titles completely tanked my framerates so some tweaking is going to be necessary.
Going back to the Vive really feels like I'm staring through a couple of toilet rolls - it really is that pronounced, but you do adapt back quite quickly.