I think the Giottos reflects similarly to the GGS - but then my Giottos coating is worn, so a new Giottos may reflect less (but I'm not convinced).
To be honest, I think reflections are a fact of life with glass screen protectors since the coatings are themselves reflective anyway - and I assume there's reasons why a more matt coating isn't used (cost, softness, reduced light transmission?).
I never found reflections intrusive with the Giottos, and didn't even think about them when choosing the GSS, not even after installing the latter. This may well be the nature of the M8, since the LCD is less a part of normal shooting than with other cameras (especially compact cameras without viewfinders and dSLRs with live view), and I, like many M8 owners, have auto-preview turned off most of the time.
A dim, difficult to see LCD in sunlight is a far more irritating problem than reflections, but that problem afflicts all cameras I've tried (and my phone!).... and is why I'm never a buying viewfinder-less camera until they sort it!
