Ask HN: Should I Use Vaadin Framework or Angular/React?

I stumbled upon Vaadin Framework and honestly really impressed by what they do. I even setup a demo application and writing code is just super easy. Understanding the framework is really easy and has good documentation. Also, similar to swing it some ways.

Our team is trying to move to a better "web framework". The issue is no one in my team including me is good in latest trends in AngularJS/ReactJS or NodeJS. We know the tech just enough to get things working, but we can't troubleshoot JS or don't know the right way to setup things, because our team has mostly C and Java engineers. None of my team member has experience in Webpack, nodejs, or any new fancy tech. We have an application based on swing, yeah, swing. And it has worked just fine for us. But, the limitations and changes in trend has finally made us to kill and re-write the whole application.

The reason, I personally like vaadin is, we can reuse some of the swing code.

My question, is anyone here have tried Vaadin Framework? How is your experience, is it worth paying for their designer and pro tools? Or we should spend time learning React/Angular instead, because most of the tools are freely available and the learning curve is high?

Thanks.

Pratyush