The Power BI Report Server renders Power BI reports (PBIX files) for data visualization and exploration, just like the Power BI web service. In terms of Power BI features and functionality, this is the essential scope of the Power BI Report Server. For users or organizations inexperienced with Power BI concepts (datasets, reports, and dashboards) and the Power BI service, these reports may be considered to be dashboards, and many of the additional features provided by the Power BI service, such as dashboards, app workspaces, and apps may not be known or utilized.

Although viewing and interacting with Power BI reports is clearly central to Power BI, Power BI as a Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS) cloud offering provides many additional benefits beyond the standard infrastructure cost and maintenance benefits of a cloud solution. These additional features support content management, collaboration, and the managed distribution of content throughout the organization. Prior to committing to the Power BI Report Server, it's recommended to understand the role and benefit of features exclusive to the Power BI service. 

The following list of features is exclusive to the Power BI service:

• Dashboards
• Data Alerts and Notifications
• Email Subscriptions to Dashboards and Reports
• App Workspaces and Apps
• Quick Insights
• Natural Language Query (Q & A) 
• Content Packs
• Analyze in Excel
• Power BI Publisher for Excel
• Streaming Datasets
• ArcGIS Map Visual
• R Custom Visuals

The most straightforward guide to the Power BI features supported by the Power BI Report Server is the Power BI Desktop application. With the exception of new Power BI Desktop features (released in the last 1–3 months), which are not yet available in the latest release of the Power BI Desktop version optimized for the Power BI Report Server, almost all features in Power BI Desktop, including the great majority of custom visuals, are supported by the Power BI Report Server. One additional and important exception to this, however, is row-level security. As of the October 2017 release of the Power BI Report Server, row-level security roles implemented in Power BI Desktop, as described in Chapter 4, Developing DAX Measures and Security Roles, are not supported in the Power BI Report server. 

Several of the Power BI service features not available to the Power BI Report Server have been reviewed in earlier chapters, such as dashboards (Chapter 7, Designing Power BI Dashboards and Architectures, and Chapter 8, Managing Application Workspaces and Content). Other features exclusive to the Power BI service, including email subscriptions to dashboards and reports, Power BI apps, and data alerts, are reviewed in the following Chapter 11, Creating Power BI Apps and Content Distribution. Finally, the ArcGIS Map Visual, which may be added to the Power BI Report Server in 2018, was included in Chapter 6, Applying Custom Visuals, Animation, and Analytics.

Since the Power BI Report Server has been built on top of SSRS, a very mature and robust enterprise reporting platform, it includes several capabilities not currently available in the Power BI service. For example, paginated reports (.RDLs) developed by tools such as Report Builder and SQL Server Data Tools (SSDT) can be deployed to the Power BI Report Server but not the Power BI service. Additionally, the mobile reports introduced in SQL Server Reporting Services 2016 and built with the Mobile Report Publisher application are also fully supported.

Furthermore, if an Office Online Server (OOS) has been deployed on-premises, Excel workbooks with external data connections to sources such as SQL Server Analysis Services (SSAS) can also be published to the Power BI Report server portal and interacted with like other reports. The ability to view and interact with Excel reports containing external data connections is not currently available in the Power BI service, but is expected in 2018. Additionally, there are plans to bring SSRS reports (.RDL files) to the Power BI Service at some point in the future.

Per the Dynamics 365 Spring 2018 Release Notes (https://aka.ms/businessappsreleasenotes), the ability to publish paginated SSRS reports (.RDLs) to Power BI Premium capacity in the Power BI service is expected later in 2018. This new capability will remove the requirement of deploying and managing a Power BI Report Server (or SSRS server) to support these report types. Chapter 13, Scaling with Premium and Analysis Services, contains additional details on Power BI Premium capabilities exclusive to the Power BI service.