The ease of use with regards to creating custom reports as well as setting up alerts and notifications when certain thresholds are crossed in order to be notified if you need it or not. They have also recently added additional features that makes this more appealing including automated quarterly withholding calculations. I wish they had more reporting options available so we could create our own customized reports but other than that everything else about their product was good! Not much at all. We were able to easily set up automatic payroll withholdings which saved us time every month.