Vantaggi
There's a surprising amount of freedom in terms of what you work on; when you start, there's a large list of available tasks and you get to choose what you are interested in pursuing.
There is almost no busy work (unless you choose to pursue busy work), and a lot of the tasks involve very cutting-edge technology.
The team is also very close-knit, and there's a pretty nice (free) snack room.
Svantaggi
Due to the relatively small size of the company and the nature of the sort of contracts 4D works on, most full-time positions are only available with very short lead times, which can be tough for interns yet to graduate. On the flip side, this approach has also led to a very high retention rate (basically no layoffs), so it's a mixed bag.