This is an old revision of the document!
There are multiple considerations you should take into account when mounting your smartphone on your motorcycle.
There are two types or smartphone mounts, either your smartphone is in a waterproof case, it is only held by a grip mechanism. The benefit of the waterproof case is that your phone is protected from water and dirt. On the other hand they might make it harder to read the screen and during a hot summer day smartphones tend to overheat. A smartphone that overheats can behave anywhere from funny to frustrating. My smartphone's GPS sensor turns wild when overheating and puts me anywhere on the map except for my actual position. Other smartphones might simply reboot, which could mean a forced stop. In addition the waterproof mounts tend to be a bit more expensive.
You will find a good overview on Amazon.