Pros
Kelly Services is a Contract employment service. It is a good place to get your feet wet in an entry level position. They evaluate your skill set, and set you up with a job at another firm. Sometimes that is seasonal, some times you can turn that into a full time position.
Cons
My experience with Kelly Services is mixed. I was placed in lower position than my skill set would warrant. This was because they did not spend any time evaluating me, they put me in the next slot that would get me hired, and producing revenue for them. kelly Services is a cheap company, and any excuse not to pay you they use. This dose not mean they cheat anyone, they have policies set up so they don't have to pay bonuses or holidays if you are even less than hour short of the policy. So if your contracted employer should observe a holiday that Kelly dose not, you get a day without pay.