BISM allows you to start either an PowerView or an Excel report direct from the model in a SharePoint Gallery. Pretty cool stuff and I really like how we have equal choice between which tool to use. You can start the report simply by clicking one of the linked report icons top right in a Gallery view (see below)
One initial problem we had is the Excel report does not work out of the box with BISM. The Excel 2010 client will not recognise the linked report and you will get a dialog box asking for the Data Link properties (see below)
The solution is to install the SQL 2012 Microsoft Analysis Services OLEDB Provider for Microsoft SQL Server 2012 which is part of the free feature pack below.
Thanks to Greg Galloway (fellow MVP) who pointed me in the right direction