They need an awful lot of grooming, they have such thick coats and they slobber a fair bit, and when they shake their heads it goes all over the walls, so you are constantly cleaning the walls.
Everything is expensive as it is for most of the giant breeds, you need more food (obviously) kennelling is dearer and you need bigger stronger collars and leads, you need a large vehicle to transport them and so on.
Some lines don't live quite so long, about 8 or 9 although that is much the same as Danes.
Most have lovely temperaments though,