@BethBowers is correct. I will add that the Connector model (not included in maintenance) is required under two scenarios: 1) multiple company access (ie, financial consolations or combined operating data). 2) Custom data containers are needed. In our experience, when developing non-financial reports, custom containers are nearly always needed. These present options to pass SQL to the Providex data and really pump-up the report development functionality.
Note: If customers have an RD server is use, the non-subscription model can be quite reasonable when leveraging in the RD environment.