Robert Nozick has many problems with Rawls' Theories of Fairness. Not least though, is his argument that pattern distribution denies individuals the right to make voluntary exchanges of money. This means that, for example, an entrepreneur sells a poor person something, but is taxed on the income from the sale, and the tax is returned to the poor person in the form of either money, or a public service of some kind. This process is fraught with problems, not simply because, as Nozick says, it commands individuals to make exchanges in a certain way, but because makes individuals react to the control in a negative way. It's often said that rich people don't really pay taxes, because they just pass the cost of the taxes on to the average consumer by raising prices. In practice, this continually makes the poorest people in society stay poor, because just as they are the recipients of a redistribution of wealth, they are giving that wealth back to the rich in the form of higher payments for exchanges.
Nozick seems mostly worried about the liberty of rich people, I think, but as even Rawls will acknowledge, people seem to be supremely self-interested, and are repelled by challenges to their liberty. As a consequence, their actions when their liberties are challenged tend to have the opposite effect intended by a Rawlsian redistributor, oppressinging the economic liberties of the poor which he'd intended to save.
Ownership is important to Nozick as a consequence of liberty, and he sees that liberty as supreme. When you are not allowed to give somebody something voluntarily in exchange for a possession of another kind, then you effectively do not own that object. When you do not own the products of your labour, then you are not free. While I agree with Nozick that ownership is an important consequence, or more properly an indicator of liberty, I don't think that pattern distribution can ever limit one's liberty, unless those whom Rawls wants to handicap let him do so, by not raising their prices or lowering their wages.