I would appreciate any advice from editors or authors who have hired an editor for copy editing.

I recently added a copy editing service to my blog after gaining some experience in the editing field; I've now edited five novels, three of which have been self-published onto Amazon and other retailers, and two of which are in revisions and will be queried out to agents or self-published if that doesn't work out.

I've been spending a lot of time on kboards.com and there seems to be a debate on how a copy editor should charge: XXX per word vs. per page. I'm sure there are pros and cons to each of this. I don't mind charging per word is that's what an author prefers, but I would want to charge the equivalent of about $2 per page (industry standards being that 250 words equal a page, or something like that). I've been going per page since that is what the author that I first worked with suggested. But not every page is entirely filled with words, so I want to come up a payment that is more fair to her when her next book is ready for me.

If you're an author, which payment method do you prefer and why? What is an appealing rate to you?