Essay editing services and plagiarism.

I've been thinking of having my paper edited/revised by an online editing service. They say that they only proofread and revise, which is not plagiarism. I'm not looking to buy an essay, I just want the corrections. Has anyone else tried a service like this? Can I get into trouble or is this legitimate?

Thanks.

I suspect that the level of "editing" such sites offer probably does cross the line into plagiarism. So, no, I would have to say it is not legitimate.