I'm having real issues with the back cover. The very first 925 back cover could be pushed in at the top of the device, like many users already reported, it was making clicking and squeaking sounds when pressing on it. Also the power button was flushed in, looked like it was always pressed. So i had it exchanged for a second one, where the exact same issue with the back cover happens, except it can be pushed in different spots. On this second device, the vibration is also very very noisy, completely different from the first one. It feels different too. I'm on my way to get my money back and try to buy it from a different retailer, hoping all these annoyances will be gone but if there is something wrong with it again, I'm afraid I'll have to choose a different phone.
EDIT: 3rd device and again, exactly same issue with the back cover, when I swipe my thumb from the right of the camera outwards, to the edge with no buttons, it makes a loud click as something snaps into place, but as I let go, the cover slightly pops up again, it's not flushed into the metal body properly, going to have to go to that store again and get the money back, for the second time now, I give up on Lumia 925...