A great place to launch your sales career
Pros
You will gain a ton of experience working with a multitude of industries, personality types, and sales situations. You will develop a strong backbone because you hear no a lot. ADP has one of the best benefits packages I've seen. You have a ton of resources at your fingertips with a company as large and as powerful at ADP, and if you use them, you will learn a ton. You can make a lot of money compared to what you might be used to if it is at the beginning of your career.
Cons
Top reps seem to reach their capacity for compensation and work extremely hard doing so. It is all new business sales, so what you do every month/year doesn't build on the previous, which is frustrating. There are a lot of internal and client issues that sales people have to deal with, and there is a lot of time sucked up with administration. They also track all your activity.