[btown]

If all you need is to diff documents (Word, Excel, PPT, or arbitrary PDFs) then I can't recommend https://draftable.com/compare enough. It's an amazing tool. Granted, you need to do merges manually with just a diff tool, but that's not usually the bottleneck.

[emodendroket]

Office comes with a spreadsheet diff tool since 2013 and I think there might be something like that for Word too.

[TickleSteve]

There is. There is also 'diff' integration with the Tortoise range of tools also (i.e. TortoiseSVN, etc).

[vxa_victor]

Seems like Draftable does not support Excel files.