We have used Reportbuilder for several years now, and we think it is awesome. We use it to build reports in our tools, as well to let our customers to build reports by their self. The End user reporting capabilities are the same as the developer. All can be customized where needed in native Delphi code.
I think every thinkable report solution can be build with ReportBuilder.
Beside a great tool they deliver also good support on the product.