Here's my experience from trying to find a "legitimate" site to order from (legitimate in the context of having the highest chance to write to a quality standard if they agree to do it).

I have a very specialist dissertation topic and rather narrow question. Going into this I still expected them to be able to write it as they should have hordes of eager writing slaves with doctorates all over the country. That expectation was soon dashed.
- Submitted order with the Academic Knowledge network of sites. They have different prices on different sites, which I had gathered has to do with their "writer quality tiers", so I just picked the most expensive site. Customer service and order management system is excellent, got a call straight away to discuss the brief. There is a site to login and see all messages exchanged. Unfortunately after up to a week they still hadn't been able to find a writer.
In my view this is actually a really good sign. Clearly the worst thing that could happen is that someone agrees to do it when they are unqualified, get paid, and give you a crap job the day before the deadline. My topic is very specialised so I can understand it totally.
- Submitted order with The Oxbridge Research Group. Their email went to my spam box, so watch out. I didn't get an order confirmation or anything until they said they had found me a writer. From that point they came back very professionally and personally to discuss brief and payment structure. My 'concern' with them if any is that (minor) they don't have that same kind of customer service system as Academic Knowledge that actually lets you know whether things are happening or just go into a big black hole and (moderate) that they WERE able to find a writer when the others couldn't.
This shouldn't be intepreted as a shill post, because clearly the ones I have the most positive feelings about are the ones that DIDN'T end up writing for me. TORG seems tentatively good, but the proof is in the pudding, and I don't have any pudding yet.;)
Also note that none of these demand payment until they have found a writer. The Academic Knowledge site network passes you through to payment as soon as you place an order but it can safely be ignored.