People. Like most work in professional services, the partner who sells the work is not necessarily the person who does the work—in many cases it would be an inefficient use of his time. Even so, there are partners who actively own a client relationship and there are those who disappear to sell other work. You should meet the people who will actually conduct and manage the audit, not just the partner in charge. You should get a sense of their strengths and weaknesses, which should complement those of your finance team. Try to gauge their overall aptitude and intelligence. Are these are people you trust and want to work with? If not, keep looking.