I’ve been around the writing business for quite a few years, and the posts I’ve read in this thread are pretty much on target. It’s impossible for a writer to be objective about their own work, which means it’s a good idea to have the work professionally edited. The problems are the cost, and knowing what you are getting for that cost. There are many editors out there -- copy editors, developmental editors, and editors who do it all -- and finding the right one for your work can be a daunting task.
Beneath a Buried House
http://www.amazon.com/dp/B003SE7J6I