This component is fast and Vaadin-compatible. That is why we decided to give it a try in our product. However, we spent most of our time fixing UI bugs and timezone issues. For example, resizing a bar will sometimes slightly change the end date by 4 minutes and if you have written code to snap the bar to the next day, you have to do a lot of bug fixes to get that to work.
In addition, if you open a Gantt component on top of another Gantt component, sometimes the grey grid disappears, sometimes the date legend is cut into half (like you see the legend for the first couple of days and the rest is blank) and sometimes the grid lines will go out of order, as if they follow no special positioning with regards to the dates they represent.
Finally, if your end users use a touch-enabled device and they view this component in a second (normal) monitor, the onClick event is not processed correctly, resulting in user clicking on a bar and nothing happening. We had to instruct our users to move the browser to their touch monitor to be able to move bars / click on them.
All in all, although I think the core of this component is promising and very fast, it did disappoint us in production and we decided to go with vis.js component instead.