Pros
None. This USED to be a good company to work for. It's not anymore. Paychex doesn't care about their employees at all. My particular office has had AT LEAST 14 (that I can think of off the top of my head) Payroll Specialists quit in the last 6 months and we've had 2 supervisors step down. Work load continues to go up with no match in pay. Clients are becoming increasingly nasty, and some of that has to do with constant employee churn. Those of us still working there are expected to put up with the abuse with a smile.
Cons
Everything. Don't work for Paychex. It's not worth it. You will be over worked and under paid. You will be verbally abused by clients while managers act like you could have done something different to have had the call go differently.