We love our structural editing service (see details) and think that 99% of writers would see their manuscripts improve markedly as a result.
Copyediting is different. For example, it makes no sense to edit copy if you still have structural work to do – just as you wouldn’t hang wallpaper before the walls were complete. And writers wanting traditional publication shouldn’t need copyediting – your publisher will take care of it.
That said, if you want to self-publish like a pro, or just want a really clean manuscript, then some form of copyediting is essential, and we’d be more than happy to assist!