Wow, this discussion has gone so far from the topic that by the end of the thread I had to scroll up to read the question!
After reading all the posts here, it seems to me that the Internet is a bad bad place after all, and essay writing is a dirty business. All you people here trying to accuse and insinuate each other's businesses - NOT COOL. You have turned what could be healthy competition into some kind of war. And DaveM is right about one thing at least - that you will all lose out in the end because your customers will become more and more confused.
Since I've used the website in question, I feel compelled to share my experience: I was short on time so I needed help with the research and found the 'dom group' of websites - one of which was dissertationdom. (No, I don't know what 'dom' means still.)
The paper was on psychology and they delivered on time as promised, but of course it was not awesome - just alright. Much better than 'crappy' still, and I was able to use the references. Some of the references were outdated though, but fixing that didn't take me much time. Overall, if I was a professor, I would probably grade that paper with a B-; or at least a C+. So Sharon88, it really depends on what kind of service you're looking for, and each website/company probably employs more than a few writers, some or all of which may be working as freelance writers. And you're smart enough to know a good writer could have a bad day or a bad writer could have a good day. One rule of thumb is, when you work for someone else rather than yourself, quality is compromised.
Someone suggested earlier that you should give them a smaller project before purchasing anything major just to test their skills. I think you could give that a go. WritersBeware seems to be someone with genuine concern and you should listen to what he says because he/she often makes a lot of sense, but I am certain he/she must have some agenda too and well, no one can be completely unbiased.