That's all very nice, but MS is a software company. I'll admit I was thinking of cross-platform development environments, like their announced open source .NET, about which I know little, and I don't really count stuff they sell as end products. I will acknowledge that this is bias on my part.
OTOH, ... you actually use those things on a tablet? As other than file viewers? (You didn't say you did, so perhaps I'm misunderstanding you.)
That said, if I'd been thinking of consumer end-products I'd never have made that statement. MSOffice for Apple has been out for ages...and MSWord 5.2a for the Mac was the best word processor I've ever used. Far superior to any later versions, and it fixed a lot of bugs from the previous versions. These days it wouldn't be so good as, of course, it didn't handle unicode, but that's still the only improvement that I know about.