Pros
PAREXEL seems to hire very positive employee's and the overall environment is very supportive. The salaries are competitive with other CRO's and I think might be a bit higher once you're above the entry level position or coming in from another company.
Cons
It's a CRO so travel is the primary thing that creates CRA turnover. While they try to keep folks regionalized, it is a challenge for any CRO to do this consistently. However, they do listen to you when you are stretched too thin, but it often takes a long time to reduce the travel. As a CRA your performance is based on travel verses quality and that is a problem, but again, it's a CRO and I think that is the nature of the beast being a service industry provider. It's challenging to get everything done with the amount of travel required, this results in really good employee's often receiving the same annual increase as mediocre employee's and this does not result in positive incentives.