Pros
Great way to get a foot into the door at a great company if they are willing to 'try you out' before hiring you.... If the were as responsive as they promised in the intiial placement interviews -- all would be well. If you can find a good position with future growth in a stable company, take it but watch them like a hawk!
Cons
In my experience, once you are placed you are considered an inconveneince. My experience has been that they are willing to blame each other -- its payrolls fault, no its your recruiters fault... They are unable to make ammends and the burden is on you to wait out their mistakes. I have found that even calling their coporate office in Atlanta wont help the resolution of your problems. I have experience 50% of my paydays to consist of issues (Inacuracies, missed payments, subtractions from overpayments, etc.)