I like that it allows you to use XML data for your reports in addition to standard SQL Server stored procedures/functions - this makes our development life easier as we can make changes without having to have someone who knows how Excel works with these formats.
The product has been around forever but still lacks some of the newer features offered by more modern products out there today (e.g., X++). There are better alternatives now so if you're looking at using something from Microsoft thenβ¦