In my Indie Writer's Pledge of Quality, I said that I would never publish anything I wrote without it being reviewed by at least three pairs of eyes besides mine. The benefit to you, gentle readers, is obvious: a greater likelihood that typos, grammatical errors, and the like will be caught, and that there will thus be fewer flaws in the book you ultimately read.
But as I've plugged away at Atticus and at The Void (Weaver #2), I've come to realize that there are some benefits for me, as well.
Reassurance: I started writing Atticus because the idea of putting a zombie on trial for eating brains tickled me so pink that I couldn't let it go. I had to put it on paper. That's what I thought as I plotted out the major points of the novel -- the main characters, their relationships, and the course the book would ultimately take.
But then I sat down to write, and something odd happened -- all that confidence went away, to be replaced by fear.
Nobody's ever done an urban fantasy legal thriller before, said my brain. Of course the idea appeals to you, you're a fantasy geek and a lawyer. For you, it's heaven. But after you write the book, you have to be able to sell it. Are you really gonna be able to do that, Johnny-boy?
(Yes, my brain really did call me "Johnny-boy". I can't explain it either.)
So I sent the first chapter around to a few people whose opinions I trust. They all, without exception, told me I was onto something. Many of them even said they liked it better than Weaver.
It was those votes of confidence that let me get past the fear and finish the book. Without them, I would never have finished it, much less published it. Which would have been a real shame, since quite a few people like it..
More perspective: Just like in life, different people have different views on the same person, action, or set of events. After a couple of WRITING SPRINTs ((c) Jane Espenson, all rights reserved), I'll almost always fork over my new material to the beta readers and ask for their input. I don't want line edits -- those are always the last thing I do. Rather, I'm looking for info on their emotional reactions to the scene, the characters, their actions, etc.
If I relied solely on one person for perspective on whether my characters were likeable or whether I was hitting the right emotional notes, I'd have taken many a wrong turn in my (brief) writing career. Me and that other person might simply have different tastes in fiction. Or they might come to a scene with a different set of experiences and assumptions than I do, or than other readers will (for example, SPOILER ALERT, a reader who had been abused as a child might have a more visceral reaction to the character of Ainsling Cronlord and be less inclined to forgive her or see her good points than one who had not.)
So I follow the old maxim: if one person says something, they might be wrong. If multiple people say something, it's time to at least think about it.
On the other hand, sometimes one person sees what others miss. For instance, when I wrote the first four chapters of The Void, I showed them to two of my beta readers, who were generally pleased. But I wasn't pleased. Something was wrong. I couldn't figure out what it was until I showed the chapters to a third beta reader, who pointed out to me that the tone was simply too comical and immature for a series as gritty as The Weaver Saga.
More potential sources of good ideas: As brilliant as I (want you all to think that I) am, I can't come up with everything by myself. I'm blessed to have a group of highly engaged and active beta readers. They care about the stories I'm telling almost as fervently as I do, and are just as (or sometimes far more) creatively brilliant than I am. So I never know when one of them might say, "John, based on this, I think you should do this next," which will lead me to smack my forehead and wonder why I didn't think of it first.
Best example I can think of to date. The opening chapter of Atticus for the Undead features the trial of a teenage girl named Sabrina on charges of witchcraft (yes, really). I originally intended that chapter to be the audience's "courting period" with Hunter, so that they could get a basic sense of his personality and motivations before I started throwing in other characters and plot points. Sabrina was not intended to appear in the novel after that chapter.
Then one of my trusty beta readers said, "John, you CAN'T make her a throwaway. I like her too much."
Well, I won't say any more so as not to spoil those who haven't read it, but at this point, I can't imagine the novel without her as a central character.
And these are just some of the 1,19831981 Reasons Why John Loves His Beta Readers.