Hello Eme.
I use it professionally, in the context that I have implemented big parts of the front-ends of my company's CRM and ERP on ABMaterial.
In addition, I am constantly adding/migrating new capabilities.
Pros: It's free (Thank you, Alain!), Really Rapid Application Development, Excellent support in the Forum, No need to install software on any user device, application accessible by virtually any internet-connected device.
Cons: None, for me.
I saw in another post, that you are worried about the learning curve and support/tutorial.
In my case, during the initial stages, I based the first pages of my App upon the Feedback and Demo applications.
I was able to create virtually any page I wanted after 1 or 2 weeks of experimentation (1-2 hours per day).