All the editing in the literary world cannot help a badly written book.  The same can be said for a great story.  If it is badly edited nothing but a forgiving fan of the topic can help.  The big thing is how damaging that can be for a first time Author who is searching for an audience.

In the case of my own book, I didn’t have the support or the resources then, that being a member of  IAIC (Independent Author and Illustrators of Canada) offered me a year after my first book launched.  I was alone, just the Internet and me.   I found sites offering good advice on the subject of editing.   I found a particular site that suggested that a self-published Author could save money by hiring a high school English teacher or an English major to edit for you.
This to me was perfect. I could save some money and find someone local who could use some extra cash.

My son’s high school teacher gave me two names.  One worked as an editor and the other was a retired English major.  I chose the latter.
My manuscript volleyed back and forth between her and I numerous times.  She made character suggestions and I agreed with her advice.
She sent me back the hard copy for the last time and told me if she were to do this again she would most definitely charge more.
I made the final changes and double-checked it against her copy.  Then sent it off to the printer and was in my glory waiting for my shipment to arrive.

As my tears of joy dried when the books first arrived I set about selling them and looking for notable people to do book reviews. 
It was not until six months later when a huge magazine told me that they had to refuse to do a book review for my book.  She felt it was a very good and interesting story. But there were many grammatical errors and could not in all fairness to their audience publish a review that would do the story justice.  She did offer to do a review on the book should I decide to re-edit it and I should contact her.
When she was told that I did hire an editor she was shocked and volunteered to stand up in court against this person should I choose to take that route.

I have decided not to add mayhem to misery and I will continue on. 
The book has been re-edited and I am ready to essentially start over, taking the lessons learnt and rebounding nicely I might add. 
So this is my second chance to make a first impression. 
I have hired an editor for my new book and will be hiring an agent to help defer any collateral damage from the first lot of books sold.
Months later, the book My Mezeppa is getting wonderful reviews.