It depends on what your goal is. If you simply want to submit something to your teacher or professor, no matter what it is, just as long it is not copy/pasted from somewhere – it will most likely be enough. If you are willing to get a good grade and produce a favorable impression – less likely so. Although research writing companies usually check their works for plagiarism and it is not very difficult to do so on your own, when it comes to quality of writing the situation is less pleasant, especially if you are not good enough at the subject to check it yourself. And judging by the fact that you are ordering a paper from someone, you are probably not that good at it at all.
The only way out in such a situation is to find a good writing service, which sometimes may be not less difficult than to study your discipline and write the paper in question on your own. The very nature of this business presupposes that there is very little quality control – the only thing that keeps this or that service from providing their clients with second-rate content is their own conscience and willingness to retain their good reputations. Taking into account the fact that such companies provide services which are generally considered to be not all that reputable as they are, the second consideration is not very popular with a lot of such organizations.
The first rule you should follow when dealing with writing services is not trust anything they say unless they can prove it. They say that their texts are written by native English-speaking PhD-holders? Unless they produce a paper of corresponding quality you shouldn’t believe a word of it.
The same goes for all the other aspects of their work: attentiveness of proofreading, profoundness of research and so on. It doesn’t mean that they necessarily lie to you – you can find all sorts of people working for such agencies, and some of them are genuinely good at what they do. But the possibility of bumping into a good writer is much lower than that of receiving a really pathetic piece of writing.
In other words, if you don’t know of a writing service that is certain to produce high-quality texts, by ordering your paper from someone you swap one difficult job for another: the one of writing to the one of finding a competent writer.