The First feels very well built. I like that the back surface is completely flat: this makes it easy to type on the First when it is laying on a table, for example (this is something you cannot do with the HTC One, which has a curved back surface). All the side edges are curved comfortably and have no seams, not even where the edges meet the display, which is tapered. There's nothing on which to catch your skin as you hold it. It is smooth.
The First's front surface is mostly the display, buy meizu cell phone but there is a thin bezel above the display and a slightly larger one below the display. The lower bezel is where the three capacitive buttons are located. They each worked well, and offer haptic feedback. There's no logo on the front, so the buttons are the only thing breaking up the otherwise solid black piece of glass.
Located on the left edge, the volume toggle is a dramatic improvement over other recent HTC devices. It has just enough of a profile to ensure that you'll find it easily, but not so much that it'll bug you when holding the device tightly. Travel and feedback are quite good. The only other button is the screen lock key, which is on top. It, too, has a good profile and excellent travel and feedback. Both of these buttons work better than their counterparts on the pricier HTC One. There is no dedicated camera button.