Warning - I thought of this post while brushing my teeth.
Editing is like whitening your teeth.
You may just need a quick brush to polish it.
I equate that to the whitening toothpaste...you won't get too much bang for your buck. But it's better than nothing. If you are an experienced writer, with years of manuscripts behind your belt, then this might be the choice for you. (I was naive after finishing my first draft of my first novel and thought this was all it needed...boy was I wrong.)
Then there is the do-it-yourself whitening kits.
You know, the Rembrandt Whitening System or the Crest Whitestrips. This is the editing that most of us do...some help from the critique group, some flushing out of characters, cleaning up plots and emotional arcs. Time consuming, but effective. And cost efficient.
Finally, there is the go to the dentist and have them put the radioactive goop on your teeth under the light and walk out with TV worthy teeth.
I think of this as the legit, professional editing services. You walk in not realizing there was a stain on that incisor (or inconsistency in your character dialogue) and walk out with something shiny (though you do have to put in the hard work of actually making the changes). Granted, you also walk out with a flatter wallet. And I wonder how much you learn and improve by doing it this way.
Disclaimer: I have never had my teeth professionally whitened, or even unprofessionally whitened. Nor have I gotten my manuscript professionally edited...so I'm just guessing about how helpful it would be.
So now your teeth are white and shiny. But they are still the same teeth. And your manuscript is still the same story you fell in love with. And now it is one you can proudly show the world.