It is a choice that you will most likely live with for a long time. Clients appreciate an environment which allows them to get into and out of your office quickly. Throughly check out the product. Examine the literature, either on-screen or printed. Features, screen appearance, report formats, performance, and support are all very important.
Different vendors market their products in different ways.
Some vendors will do on-site demonstrations of their product. A demonstration and discussion of a full-featured system can take two hours or more. Ask the salesperson how long the demonstration will take when you make the appointment. Try to arrange a time when you will not be interrupted. Have some other members of your staff present to ask questions that you may not think of at the time.