I talk from my personal experience with V1 and other devices using waveguides display, I felt like it is not the best type of display to do "heavy work" such as reading/coding. It is quite annoying to have everything ghostly, even if the tracking is stable and the resolution is good.
I've never tried any of these devices, but the one thing that comes to mind is that I wonder if you might get eyestrain trying to use it for 8 hours a day. When working on my laptop, I'm constantly switching focus -- looking out the window, then back to the lap top, then at the wall, etc, etc. I think that kind of thing might end up being more difficult.
You can still switch your focus with these because you still see the real world. However it is true that the objects are rendered ("OpenGL-like") the same way no matter where the object is located in the scene, so while it gives you the feeling that you can focus your eyes on the object (because of their 3D position and the tracking), the objects always appear "clear" which can be annoying. That said, using them 8 hours must be hard : the virtual objects emits unreal lighting (different and stronger than the light reflected by real surfaces)
