All of them (and many more) are actually the same company. I should know. I worked there.
That company is 4writers, and it is headquartered in, of all places, Rivne, Ukraine. The pictures on these sites are of Americans, the prices are in American dollars, and all the toll-free numbers are in America. Strange, then, that they proudly advertise "100% native English speakers." It's the sort of thing that should make you suspicious, like when a butcher shop feels the need to assure you, "NO human meat!"
The truth is, none of the writers are native English speakers. Many are native Ukrainians, often students themselves (never mind that the sites promise all their writers have advanced degrees), who work out of offices in Rivne and Lviv. The rest tend to be freelancers from Kenya. Being uniquely Canadian qualified me to distinguish good English from, well, barely English. As one of their editors (and, briefly, as a call-center agent) I had a front row seat to the seedy world of academic cheating.
4writers is one of a small handful of academic writing companies (each owning dozens of websites, to give the illusion of limitless competition), and literally all of them are located in Ukraine. Why Ukraine? Because while the relatively measly amount of money (around $5 per page) isn't something American freelancers would salivate over, it is a significant draw in a country where the average salary is around $200 a month. Paradoxically, even though Ukraine is poor, it nonetheless has an extremely educated, motivated, and literate workforce.
So basically the opposite of the customers buying it.
A really dedicated writer - one who puts out 300 pages a month -- can make $1,500 for it. That doesn't seem fair pay for what's basically a novel's worth of output in four weeks, which is why this kind of company wouldn't fly in America. If not because of the meager pay, then because of sheer illegality. But Ukraine is, well, flexible - and I'm not talking about their excellent gymnastics team.
Hiring a foreigner with limited knowledge of your culture -- not to mention your language -- to write something as complex as a term paper is a bold gamble, and you can't always count on the proofreader (also Ukrainian) to catch the worst of the errors. One paper I edited included a survey of youth in Baltimore. The student who hired us was supposed to design and carry out the survey, but instead insisted the writer fabricate the results in a convincing manner. When asked their favorite sports celebrity, the urbane kids of Baltimore overwhelmingly picked Barcelona footballer Lionel Messi.