I used to use a LCD hood with a lens that my kids bought me in Japan,
but I eventually lost it and bought ClearViewer.
The LCD hood was really great as all ambient light is blocked while that's not the case for ClearViewer. Also, using hand for blocking the light interferes with my physical movement when using bigger lenses/telescopes hand-held because usually my left hand is supporting the weight of the lens and adjusting the focus at the same time while my right hand is adjusting shutter speed and pressing shutter button.
But the hood is bulky, ClearViewer is not, and that's one truly GREAT advantage of ClearViewer especially for native lenses IMHO.