The thing I like best about Shimano is, oddly, exactly the same thing as I loath the most about them. Namely, that they never give up on improving stuff.

They have never made a really good internally geared hub, but they kept trying even when the rest of the industry had pretty much given up on internally geared hubs; and Shimano hubs keep getting better. I still don't like them, but their influence is really good. The same goes for their dynamo hubs; better in some ways than the original Sturmey Archer ones, but some of the improvements are not improvements at all. I'm really glad they make them, though.

Shimano's improvements to the shape of freewheel/cassette teeth, and to chain plates, have been widely copied and for good reason. Their centeron derailleur jockey is also a brilliant idea.

I think they made significant improvements to the shape of freewheel/cassette teeth and the shape of chain plates. Also, the centeron derailleur jockey is a really good idea