They've cut shrinkage and given themselves real data on which to base decisions. They've been able to motivate and monitor employee performance and cultivate better customer relations. It's work, no doubt. But you already work hard. It's time you get paid for your efforts.
Every store is different.
So, every system is different. Security, reliability and performance are all effected by what you buy. Don't forget to consider Point of Sale scanners, cash drawers, receipt printers, report printers and tag printers. In most cases its more cost efficient than 'figuring it out'. Include a service and support contract.