I am looking forward to excel online matching the desktop version with it's capabilities!
Sometimes the formatting on Microsoft online can be wonky. It's only in the desktop version (sorry if that's not the technical term for it!) where I feel really comfortable with the formatting and more options.
It's SO frustrating to pull the document out of SharePoint, save it, then reopen it into Excel and have none of the changes come through even though they can be seen in Excel online.