Pros
The people, my colleagues were really great to work with and am still friends with many even though no longer there. Benefits were also very good. Your experience at Premier will depend greatly on who you have as a manager so if you get one of the good ones which there are a number of there, awesome.
Cons
Work life balance continues to be a farce and in many cases its expected to work overtime each week. Uncompensated overtime for salaried employees. IT at one point had 26K man hours of overtime in for a large project, yet staff wasn't granted anything close back for time they gave up. Unethical, incompetent, demotivational managers who never seem to be taken to task even though the right groups, people are made aware of it and provided with documentation, evidence. These are the ones who make good employees leave and drive moral down. Outsourcing work to offshore resources has become common place in IT, to the point where some groups which were 100% Premier staff are now only 25% Premier staff. It seems to be the mantra of certain leadership in IT to push it all offshore, not to the betterment of the employees.