Bumping this thread since I'm using their services as well. I'll try to post the outcome of this experience.
They usually are until they deliver a product, and you start asking for revisions or rewrites
I've asked for a rewrite for my product, which the writer said he'd do, though I do hope they don't see me as a liability. I'm not trying to be difficult, but at first it appeared the writer read a question incorrectly (and in turn the analysis was incorrect), and the result wasn't in a perfect format I would've liked. The latter issue was more of an oversight on my part - I should've sent sample answers and the relevant coursework to him in the first email. I am getting rather nervous because I haven't heard from him since his last email a days ago, when he agreed to do a rewrite, and I haven't been had a reply to subsequent emails I've sent. Well, fingers crossed. My deadline is flexible.