The ability to create custom reports for our customers with ease of use! It's an all-inclusive tool that allows us complete control over what we do as far at customization goes which makes it easy working within this software package compared other options out there like D365 or Dynamics 365CPQ (which are more expensive).
I wish they would make some enhancements such improvements regarding reporting capabilities but overall not much room here if you're looking into Microsoft products then check them off your list because its very good product from my experience so far. Our organization uses winmill mainly through salesforce CRM where users can access their data easily across multiple devices via web browsers allowing quick resolution when dealing customer issues/inquiries etc.