Please assess their quality of work.
I have found their quality of work to be very good and they have great customer service reps.
How much time and money do you estimate that they save you each month?
I cannot comment on this as I do not know the particulars.
Based on your experience, what takeaways can you share about working with them?
They are professional and they know HR inside and out. They can help prevent lots of legal issues with their expertise.
What do you think are their strengths?
Professionalism, experience, and customer service are their strong points.
Where do you think they can improve?
They could maybe offer lower cost structure based on employee numbers.