Pluspunten
The developer team is open and even eager to use new technology. If you are interested in experimenting with new frameworks and javascript libraries, you'll get support and interest from others.
Forio has the structure and size of a startup, but without the instability. Projects are collaborative across teams. People like to work with each other.
Minpunten
A relatively unstructured environment can be a double-edged sword depending on your personality. Nobody is going to give you a checklist on how to do your job well. This isn't a con if you're comfortable with ambiguity and want to take your role by the reigns, but if you're used to highly defined tasks you may feel a bit overwhelmed.
The small team size can mean that you have to work on several projects at once.