Different screen manufacturers?
I noticed a weird difference between my m8 and my wife's. When I look at my screen wearing my sunglasses (polarized Maui Jim's) it looks fine. When I look at my wife's, it's virtually invisible. Rotate them both to landscape and mine still looks fine, and hers suddenly appears like magic. This is with the phones side by side in the same conditions... For what it's worth mine is the gunmetal and hers is the silver one.
Sent from my HTC6525LVW using xda app-developers app