If the M8 shares the unibody aluminum construction of the 5 series iPhones, that's reason enough for me to skip it. That soft aluminum scratches if you look at it wrong, and gets beat up pretty badly. And, unlike the glass iPhone 4 (which was a dream to fix the back on - two screws and a slide), there's no easy way to replace the case - you pretty much have to strip it down to it's parts to get to the case. I ended up putting mine in bumper with a back, and just the microscopic grit that gets in my pocket and around the edge of the camera opening has (aesthetically) damaged the case.