I dislike them because they tend to be quite short and aren't massively effective thrusting weapons, and for whatever reason they have no useful hand guard so you'd probably have all your fingers chopped off. Plus they take years to learn how to swing effectively, when you can teach someone to use a spear in a fraction of the time and they'll probably just stab you before you can get close enough to use your fancy sword because half the time you can't even use a shield with it.

There are a lot of issues with the Katana, but they do cut things nicely, so hey-ho.