Pros
They provide pretty good on-the-job training and they are willing to hire individuals without extensive experience in the industry. It can be a good place for recent college grads or for someone who is looking for a career change. Just don't expect to stay there forever.
Kontras
It is very clear that the priority is making a profit, not caring for study participants or employees. There is significant pressure for sites to hit certain metrics, which they have no control over, and compensation is tied to those metrics. We would often say we did not want to take a study because we knew we did not have the population to enroll at the required rate, but they would assign it to us anyways and then punish us for not hitting the enrollment goals. There is high turnover.