I'm using a Mountee which has worked pretty well. Its all plastic, and the process of getting the right fit is a little fiddly, but it works as advertised and holds my phone secure.

The one thing I've noticed though is that it has actually caused a dent to appear the screen of my Nexdoc Touch due to the mounting pressure. It's a very minor dent, and it hasn't affected functionality yet (video and touch both work fine), but it has me a little worried about long term durability.

A few other minor points: It comes in a fair ways past the bezel, blocking a small bit of the screen (on both nexdock and my s9+). Due to the placement of the power button on my phone I have to mount it halfway down my phone to avoid accidentally powering down.