Pentaho serves several roles in our environment.
We use it for report design and delivery. The designer tool is fairly straightforward and once reports are complete they are immediately accessible to our end users.
Pentaho is used for Business Intelligence which includes totals, trends, and forecasts of sales and subscriptions of our services. Pentaho's web-based analysis tool allows our end-users to drag & drop measures and dimensions and instantly convert raw data into a variety of graphical representations. Before we had Pentaho, each view might have required a long query or static report that was hand-exported to Excel. With Pentaho's analysis tool, our sales, finance, and marketing teams have instant insight and infinitely flexible views of our data.
In the IT department, we use Pentaho as a scheduling engine for data maintenance jobs as its interface allows us to manage multiple shards from a single source.