There are some functions in PowerPivot for Excel that are not supported in SharePoint, at least to my experiance!
1. Even if I click on the Clear filter icon in SharePoint it's still red-marked - indicating that there are applied filter.
2. In Excel there is a Clear filter option. PivotTable tab/Option. It's needed and missing in Sharepoint
3. In Excel there is a much needed function 'Freeze Pane' where you could define that horisontal filter, Row columns are froozen at the top so that when you scroll downward they are showing up. This is not supported in Sharepoint, much needed.
This is my shortlist but it's certianly more, feel free to add more to this list.
Does anyone has a idea when these functions are to implemented in Sharepoint, is there any workarounds?