If You use it for taking video while walking it gives a good stablization, please watch some youtube tutorials for learning the Gimbal moves and how to shoot using Gimbal.
There is an app provided by DJI, the maker of this product which is available in app store and might be in Play store also., if you use that app You can shoot with some predefined moves available in that app. But the issue is that the music come along with this is not removable and You need to mute it using a video editing software.
Another problem with this app is if You use this app, it will drian the Mobile's battery very quickly I have seen 10% drain in 1 minute.
You can also use the native camera app to shoot and this will not drain the Mobile Battery which I have tested in iPhone. (The Gimbals buttons works with native Camera app too.
You need to balance the Mobile perfectly after fitting in it in Gimbal otherwise it will drian the Gimal's battery very easily, since iot need to stabilize the mobile using Gimbals motor. So I have marked two points in the Mibile case after balancing it in Gimbal so that I can fix it easily during next time. I have attached a video shot using this Gimbal
Its costlier in India compared to the DJI Site, but from the site they wont ship to India.