Pros
They pay internals on time
Cons
I worked at Premier Staffing Source for a little over a year.
From a recruiting perspective, it was a frustrating organization to work with because once you submit a candidate to an account manager there was a 10% cancel of hearing back from the account manager about the client wanting to interview. It felt like most of the candidates that I worked with we're stuck in limbo. There was a ridiculous amount of micromanaging because of the way the organization tracks productivity (which I feel doesn't work). If there was an error on the corporate side there was little to no communication about the incident until you were neck deep in angry phone calls.
If you don't work in the corporate office (as an internal employee) you work at a Regus office. My office was a little box with no windows that felt horribly sufficating and lead to depression and weight gain.
It may be a multi-million dollar organization, but it feels hamstrung because of poor leadership.