I would suggest a face-to-face meeting with one of their representatives to see if their service would be suitable for their business. We have under 50 employees, so it works very well for us. A larger company may have other specific needs.
We had previously been with another company and found their service to be quite expensive and the customer service to be very poor. We were assigned a dedicated customer support person at the other company, but it was constantly changing, and they were routinely unavailable due to flextime and part time work schedules.
With The Payroll Company, we use their full payroll processing system with deductions, tax payments, direct deposit, PTO accrual, and custom reports. They have performed quite well. They do not assign one dedicated person to your account, so you will always speak to a live person at the help desk. Most problems are solved right away. I have only had one instance where I needed to receive a call back to answer my question, but I received my help very quickly even in that case. All issues or modifications are assigned a case number for easy tracking.
They are very customer service driven. Everything from the initial set-up to day to day operations runs smoothly. We planned to make our switch within a pretty short period of time, and they were able to accommodate us.
The website is not quite as slick as what we had used previously. It is fully functional, but just doesn't flow quite as well. Also, we only have access to our payroll reports for a certain period of time. I would prefer to be able to extend that for an entire calendar year.