I've bought a few different of the gummy/stretchy ones and they're all pretty decent for casual use (I had them on my commuter bike, so daily use but not a ton of distance). They're cheap and aren't phone specific which is a nice benefit. Folks who get the quad lock system seem to like it, but it more expensive and seems to be best with a phone specific case, which is why I've stuck to the cheap mounts.

 
Personally I am a Quadlock user for reason of being super solid and for being a whole system (car holder, etc.)

But check this out. Can't be beat for simplicity:
https://getfinn.com/
Made in Austria. Haven't tried personally but heard good things about it.

I've done pretty well with Quadlock.

I use quadlock as well when I carry a phone on my bars

Many thanks all

Quadlock. Awesome product.