The mount is sturdy, and the locks are strong enough for the motors. It feels much better than manual refractor mounts in terms of sturdiness, and this is a key point. It is incredibly hard to build a sturdy refractor mount, and when they are sturdy, they are expensive. A GoTo mount solves that problem and improves upon it by adding automatization.
If there is a problem to be found with the mount, it is the inability to use it by hand. You have to unlock the optical tube, point to an object, and lock the optical tube again. The telescope won’t balance if it is unlocked. Using StarNavigator 90 NG by hand is not comfortable at all.