Pros
The best part of working for Key personnel is that you can decide to work part time or full time, depending on your availability for assignments. You can refuse to repeat a temporary assignment, if you were treated poorly by a temporary to hire company. I was able to transition from temporary assignments to full time employment to meet my career goals.
Cons
It was a well known principle that Key personnel was committed to hiring attractive people, if an employer needed "front desk appearance." This did not bother me, but it may affect someone looking for employment, who has not been trained to dress professionally, as this is a continual problem for older generations who are looking to hire a younger employee, who has not been trained that they must dress in slacks, blouse or collared shirt/blazer or suit for work. It was only a negative to people who did not want to dress professionally and to do their hair and makeup every day for a "front desk appearance" at work. If these standards, especially for women bother or offend you, then you will not be a great fit with many opportunities for advancement at Key Personnel. If you take professional appearance seriously, then this will not affect your career advancement.