Pros
Good opportunity to build systems which affect lots of users. You are surrounded with lots of intelligent people. Good location.
Cons
Very complex and messy technology stack. Excessive pressure to 'get things up and running' quickly as opposed to getting things done correctly. Freelancer.com is forced to hire an ever increasing number of engineers to manage the growing mess that is GaF (the core of Freelancer.com) and the enormous amount of unnecessary complexity all around it. There is a nasty culture of finger-pointing, blaming and scapegoating - Everyone is expected to 'take ownership' of some part of the code instead of solving problems as a team using rational constructive debate. Employee retention is very low - Very few people stay for longer than 2 years.