The ability for me to set up recurring billing as well as multiple time zones. The system allows you to keep track of your hours so it's easy seeing how much I need to invoice clients next month or week with no problems! It would be nice if there was an option for creating alerts when certain amounts are spent in our bank account instead of having to constantly check ourselves to see where we stand at all times. Great tool especially since we use this along with Quickbooks. We can easily create invoices weekly or bi-weekly without issue.