I'm using Quad Lock cases and bike mounts since 2014.
I have had a case for my Samsung S4 and a S7 (my current phone). Furthermore, I have an universal adapter for an older phone and bougth cases for an S5 and S10 for my wife.
Next to the cases I have multiple bike mounts. I started with the Stem Mount. The Stem Mount works very good, but is in my opinion a little bit too big. After the release of the Out Front Mount and the Out Front Mount Pro I bougth these as well. Currently I'm using the Out Front Mount Pro on my race bike and the Out Front Mount on my mountain bike.
During all my rides on the road and the MTB the mounting system always worked flawless. I do really recommend the Quad Lock cases and bike mounts.