Unless your thinking about throwing the equivalent of 6 figures at mining equipment and are able to secure some sort of sweet deal you will more likely than not end up with less than you started with by the time your rigs are consuming more power than they are generating in coin. <---any non pre-order will basically hit this point within a month or two at the latest.
That's not true at all. Someone with cheap power at home will break even much faster than a large mining farm.
A large farm has to worry about a/c, power distribution, and all sorts of overhead. Someone that is mining at home can have a small to medium setup with no extras at all. Sometimes the large farms let miners sit around because they take so long to setup. Someone smaller will be up and running in no time.