Pros
Pay and benefits were great, and I was lucky to be placed at 3M. Nothing wrong with working there--flexible workday, great people, labs, constant building improvements, excellent work environment. Very high standards, it is understood but never said that everyone is (or is supposed to be) a Type A workaholic and overachiever. Not that there's anything wrong with that, just don't ever think you can coast along there. Because I was assigned to 3M I had an indirect experience with my Pace managers; emails about submitting timesheets on time and the like. I actually met them during the monthly meetings (which didn't seem to accomplish much in my mind) and when I was unexpectedly canned.
Cons
Contracters are expendable, and they (your contract company) will not hesitate to drop you with no warning at all if they think you're slacking, regardless of the circumstances. Once that happened, all Pace could do was say "well, sorry, please talk to HR on Monday and we'll see what we can do."