One day, out of the blue, I recieved a job offer. With honeyed tongue, she dangled a nice wage, some decent benefits, and "temp to perm", meaning that the company was (supposedly) looking to hire the temporary worker, if that worker was satisfactory. They lauded themselves as good folks who take care of their workers.
On the tail end of this job, I realized that the worker was nothing more than a commodity, a rental unit to be sold to the client. The agency's main interest is in taking care of the client, because that's where the money is. Don't expect the agency to be on your side if there is a conflict or a problem. You'll be the problem, for even bringing it up. Workers who don't put up and shut up lose their value, and if your value drops, they drop you.
The most important thing to remember is that your work hours aren't just bringing you a paycheck; they are bringing the agency money as well. The more hours you work, the more money they get. If you're late to work, they lose money. If you have a doctor's appointment during work hours, they lose money. If you are sick and call in, they lose money. They don't like you cutting into their profits by being a human being. It's pretty safe to say that if you are not in excellent health, it's not worth your while to work for a temp agency. They won't tolerate your being ill or needing to go to the doctor.
Be wary of companies that utilize a lot of temporary help, too. Supervisors who are willing to pay a premium for temporary help are generally types who prefer the idea of "disposable people". They don't like to dirty their hands with dealing with human beings; they'd rather leave that up to the agency. The supervisor where I worked was very much this way. There was a revolving door of temporary laborers; on any given day, there were at least two (out of six) line workers that were temporary. These workers generally changed almost every day, so every morning was a training session before things could get started.
However, even those employed by the company directly were treated as interchangeable cogs in a machine. One employee, who was in the hospital, was threatened with firing if he took more than one day off to be there. Another was told, "Why don't you go home and cry like a baby about it?" when he asked to stop for a bit, because the work he was doing created blisters all over his hands. Workers are told that they can be replaced easily, so they fear being ill, or simply not being liked by the boss, who would arbitrarily decide that perfectly decent employees were irritating because of the way they looked or sounded.
I wish there were a more honorable system out there, that companies had some kind of incentive to hang on to employees that are doing satisfactory work. It seems like there is no loyalty in the workplace anymore, no security. Why shouldn't people expect that they'll not be replaced as long as they're not doing anything wrong? Why do we have this atmosphere of nitpicking the negative--employee files full of piddly mistakes, but never the good things? There is no respect for people, especially from corporations. The moment one downtrodden little man gets his hands on some power, he rarely wields it benevolently; he promptly forgets his roots and proceeds to tread on those in his employ. And it's just that much easier to do when they're a temp worker.
Say NO to temp agency headhunters.