Functions: Password recovery, protection & encryption, hiding sheets (very hidden), changing cell references,link manager (e.g. modify multiple links in multiple workbooks), defined name manager, duplicates manager, update links (in multiple closed workbooks), compare spreadsheets, spreadsheet development, data analysis, warnings (e.g. alert of manual calculation mode), vbe tools, worksheet functions (e.g. mtoolsSumIfVisible, mtoolsMergeCells, mtoolsGetComments).
Beyond the limits of Excel: Excel doesn't allow the manipulation of unlocked cells in protected worksheets, if your selection includes any locked cell. MTools does not have that limitation and makes it e.g. very easy to clear the contents of all unlocked cells in your selection. Excel doesn't allow to apply functions to multiple closed excel files. However, many MTools functions can do that. That's a feature that will save you a lot of time! Have a cup of coffee and let MTools e.g. protect your 100 spreadsheets.