I have this thing where I have grown to despise the stereotyping of the ukulele for soft, happy music. While it does work well for that genre, to me that is like saying that the electric guitar is an always angry instrument.
In my opinion, the ukulele can be as versatile as the player. Even if nylon strings tend to be soft on the ear, if the strumming or plucking is right it can be a real harsh noise. And I mean that in a good way.