Never read it and don't plan to. Little of Mill is useful in today's politics (unless your a hardcore libertarian).
Can you justify your statement, if you have never read it? This is purely for my information.
Sure. Mill's politics are basically radical libertarianism - someone should be able to do anything and everything they want as long as they don't hurt anybody. This may have held water in Victorian England, but in today's day and age pretty much everything one person does effects everyone around them. For instance, prostitution, drug addiction, and obesity (none of which would have bothered Mill) costs the state immensely in health bills.
This is merely what I've gleened from reading books about him, and true enough to really get what he's saying the best thing would be read him. But as far as I'm concerned, if your interested in libertarianism you would be better off reading more modern writers on the subject.