Hey, I told you - just some quick surface-level first impressions for now. It's a small thing, relatively speaking, but it's impossible not to notice when you start handling the phone. The buttons also barely protrude from the device and are consequently a bit tricky to find with your fingers in the first place. (The power button does have a slight texture to it, but it's not pronounced enough to be immediately obvious.) The problem is that the power button now sits directly beneath the volume buttons - and since all three buttons are roughly the same size and shape, it's tough to tell which you're touching without taking a moment to feel around or look down at the device. The M9 attempts to fix that by moving the power button to the phone's side, which seems like a perfect solution - until you use it. Up until now, HTC had stuck the power buttons on the top edges of its One phones - a placement that made them tough to reach, especially given the height of these devices. There is, however, one physical change I'm not so sure about: The One's button placement still leaves something to be desired. The M8's somewhat awkward nature was one of the few gripes folks (myself included) had with the phone, and the M9's evolution makes that a thing of the past. Things like a less slippery finish, a shorter and narrower frame, and a newly added "lip" along the perimeter make the M9 feel meaningfully more comfortable in the hand than its predecessor. To be sure, they're subtle - but they go a long way in affecting what the phone is like to use.
You really have to hold the One M9 in your hand to appreciate how much difference HTC's changes to the body have made. The physical changes from last year's phone are subtle - but significant.