
I think it may depend on the type of leather, one of our sofa's is a rough finish leather in a natural rather beaten up colour, it's been great and has resisted the claws of many an enthusiastic Staffie, the leather does mark, but sit on it a few times, and the marks just disappear.
One of my friends however, got a sofa with a fine shiney finish in a rather smashing bright red, it didn't last very long at all, the leather soon looked awful and started peeling.