Pros
Robert Half has a great training program. I was a newbie when I started in the staffing industry; I had never sold a thing in my life. Robert Half quickly and efficiently gave me all the tools I would need to be successful. It really is a matter of just putting your head down and using the tools given to you. Everyone there is driven and competitive to the core. It's great to be around that all the time because it pushes you to be better and drive harder. Ruthlessness is applauded and encouraged; you don't need to worry about being PC or polite and can just go about your business and do what you need to do to get ahead.
Cons
Everyone there is driven and competitive to the core. This turns into looking over your shoulder and being on alert more often than not. Working every single minute of every single day does not guarantee you success, and yet, that is what is expected of you day in and day out. It could pay out, but it doesn't always. Your work IS your life. There is a lot of turn over. A LOT. You become so jaded to people getting fired, that you start making bets with other co-workers how long each new person will (or won't) last. Not getting fired becomes more of a badge of honor.