Probably the one component that is forgotten when looking for a POS system is employee management. Do you have the right staffing levels for your sales? What should the schedule be for next week based on your sales forecast? It should track employee hours and sales performance as well.
By sales performance, look at the metrics of each employee. Key selling statistics like % of Sales in Accessories, # of items per ticket and Sales dollars per hour help you see the productivity of your employees. Consider this, you have four employees all working the same hours, but which one is making you the most money? This data can tell you that. It will also help you reward key selling skills behavior and we all know that what gets rewarded gets repeated.