Ventajas
I was really lucky to work with some incredibly talented and friendly people, including quite a few internationals. Many of them have gone onto more high-profile roles; however, many of them left earlier than they might have, because they found themselves (like me) frustrated and dissapointed at how the company was being run. Other pros include a decent work/life balance (office empties at 5 on the dot) and ability to negotiate better leave and pay options - but you will need to negotiate and not wait for them to come to you.
Desventajas
Key Media appears to have decided that its Australian branch - which I believe is still the most profitable - should be allowed to decline and fail. Over my four years, I saw headcount significantly reduced across all sections of the business, with many jobs being outsourced to Manila and 'de-skilled'; such as switching from Australia-based journalists who'd go out and interview people to remote writers copying press releases and other outlets' work. I believe we had the talent the overcome challenges like print ad revenue declining and changing events trends but KM seemed content to fail, retreating as our competitors took on extra staff and trialled new initiatives. The company has also lost talented people because of terrible management of HR situations - including tolerating office bullying - and the lack of career progression. As an employee, another problem is the near lack of feedback; my line manager had a full-time job and so could, understandably, only take a little time out. If you're at the start of your career this should be a real concern for you.