I would steer clear of those types of companies. They tend to be notorious slow pay. Sometimes you get lucky though, especially the first few check.
I have a Corp. client that I am going to court on soon. They me owe $2110. They aren't refusing to pay or have a problem with the work. As is typical, they just won't commit to when they will pay. The money is already lost just based on the amount of time I've spent so far trying to collect. A lot of guys would have just blown it off by now and THAT is exactly what they hope for.