SQL Server 2012 contains six new features for SSRS:

Excel Renderer for Microsoft Excel 2003, 2007 & 2010 - Excel renderer will support the Excel 2007 XLSX format.  To enable this feature, Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint must be installed.  This extension renders a report as an Excel document compatible with Excel version 2003, 2007 and 2010.  Previous versions of SSRS rendered Excel and Word files into the old 2003 formats (.xls and .doc).  This provides enhancements to the limitations of the previous version, such as increasing the max rows per worksheet to 1,048,576.

Word Renderer for Microsoft Word 2003, 2007 & 2010 - Word renderer will support the Word 2007 DOCX format.  Like Excel Renderer, to enable this feature, Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint must be installed.  This extension renders a report as a Word document compatible with Word version 2003, 2007 and 2010.

Power View (Project “Crescent”) – A new interactive data exploration and visual presentation experience.  See SQL Server 2012 (“Denali”): Power View (“Project Crescent”).

SharePoint Mode - SharePoint integration has been re-architected to improve the admin and user experience.   The new architecture is implemented as a SharePoint 2010 shared service which allows Reporting Services to leverage many of the IT features of SharePoint products.

Data Alerts – Alerting is like a subscription driven by changes in the source data.  This will give users, among other things, the ability to get reports delivered to them when changes in a data source raise events on the server.  So when a price goes down or when a measure value falls below a target value, reports are delivered to a user.

Report Server Projects in SQL Server Data Tools for Visual Studio 2010.  An add-in to Visual Studio 2010, SQL Server Data Tools (SSDT) is a development environment to modify BI Solutions.  With this tool, you can create, open and modify Report (rdl file) from version 2005, 2008 and 2008 R2.

More info:

Quick Look – Data-driven alerts for SSRS in SQL 2012

What Will Be New for Reporting Services in 2012?

SQL Server 2012: new features for Reporting Services (SSRS)

File Formats for the SQL Server 2012 (Denali) Reporting Services Web Services Renderer

What’s New (Reporting Services)