According to the latest BI magic quadrant from Gartner Microsoft is once again positioned as a leader. I'm glad to see the praise for Microsoft's "BI in the cloud" strategy :)
One common complaint I heard was the lack of metadata capabilities and this will be resolved in SQL Server 2012. I have never been a fan extensive metadata use in BI though. With other tools my experience was always that the time spent to fix the metadata to reflect underlying data changes is more than to fix the report itself. It's still good to support both methodologies and leave the decision to the users.
For Gartner's report please visit http://www.gartner.com/technology/reprints.do?id=1-196VVFJ&ct=120207&st=sb