Replied 22 August 2018, 9:36 pm EST
Active Reports and FlexReport are two different reporting tools and are used in different context. FlexReport comes as a part of ComponentOne product, whereas ActiveReports is a dedicated reporting solution and would also need a separate license.
FlexReport serves the purpose of creating, designing, editing, previewing, importing, exporting, and printing of Reports to various platforms like WinForms, WPF etc. You can have a glance at its key features using: http://help.grapecity.com/componentone/NetHelp/FlexReportWPF/webframe.html#KeyFeatures.html
However, Active Reports is a dedicated product with Fast .NET Reporting Engine and Flexible .NET API for generating, editing, viewing and exporting Reports. Active report supports multiple Report types namely Section, Page, RDL and XML based report types to fit your .NET reporting needs. Also, it includes stand-alone 'ActiveReports End User Designer (EUD)' which can be customized and embedded within your projects to allow end users to create ad-hoc reports for themselves. It can also be used to design reports when you do not have Visual Studio IDE installed. Furthermore, it also include Visual Query Designer to generate optimized queries without SQL language expertise and provide customizable viewers. For detailed information about the same, please refer: https://www.grapecity.com/en/activereports
Regarding converting your old *.rpx reports you might want to refer the following link: http://help.grapecity.com/activereports/webhelp/AR12/webframe.html#ImportingRPX.html