Pros
Positive working environment with communicative and empathetic leadership. Maintained great client relationships and has a strong foundation for people looking for an entry point into the QA world. Never in my time with them was there mandatory overtime, nor did I ever feel punished for not participating in overtime. They maintained a very strong work / life balance and always encouraged people to take care of themselves.
Cons
As a contract-based QA company, the timelines for promotions rely heavily on number of contracts and budgets. So when contracts are plentiful there's lots of room for rapid growth, but when contracts wrap up with no new ones lined up, it can cause career stagnation even when ready for a promotion. When contracts change, headcount also has its ups and downs. While this is typical in this industry and I wouldn't hold it against Experis directly, it's still tough to go through.