Comically bad
First off, the UI is abysmal, theres no way to navigate where you're up to in the video without zooming out and zooming in on a tiny bar (which is incredibly difficult to get right)
Additionally, there's seemingly no way to select multiple clips on the tracks in order to mass copy/paste.
After 30 minutes of trying to literally just copy/paste a 2 second video file, with the second one reversed to form a longer video loop, I finally exported the file.
The export system is seemingly broken. The file was completely distorted, random colours filled the screen in big bars and it was completely unintelligible.
Absolutely do not waste your time on this finnicky app, try the desktop version instead which is far better and easier to use, and also has a functioning export system.