Pros
It was a nice place to work in a lot of ways. When I was employed there, Freelancer was a great place to launch a career. It was also a great place to learn from talented engineers and data scientists and product managers. It was also very empowering! There were only a few barriers to putting ideas into production. It also throws a great party. But please check my cons section, because very few of the pros are there any more.
Cons
Freelancer is slowly imploding. The management don't know how to retain talented people. When I started there were a lot of really talented people working there, but by now most have left, replaced by interns. In fact, if you are looking at an internship, remember that if you're looking to actually learn things, you want to be placed with senior engineers, not with more interns. The reason everyone leaves is simple: the company doesn't take a long term view on anything, which drives talented people crazy, so they leave. It's a stressful place to work, and it pays poorly.