Seen no problems with office 2010 and 15.1 with export to excel (data only). i.e. output is good and rendered correctly.
This was the case in object list views, object portlets and nsql portlets, doesn't look like the underlying XML changed.
Whilst that's not the same as CA saying it's supported, I hope that's useful.
Note: the export to excel still doesn't play nice with the app server, hide it!