I've read on your blog that you place value in a writer's voice, and other agents, such as Jessica Faust and Rachelle Gardner, agree that it's important.
I've also taken classes and read writing tips, such as Allen Guthrie's, that say one's voice should not creep into one's writing as this authorial intrusion detracts from the substance of a work. (Ref: Hunting down the neoplasm, item 11) or here
Should I assume people are using the word 'voice' to apply to different stylistic aspects? Or that there is good voice and bad voice? Or merely that different readers want different things, so while some consider a strong voice a plus, other consider it an annoyance?
Hmmm- that's not very helpful is it?
I had to think about this for awhile. Voice is one of those ephemeral "musts" that drive querying authors mad because there is no objective answer. Unlike spelling, format and word count, there's no way to measure voice...but I know it when I see it.
I know it by its energy and confidence. I know it because it stays in my head. I know it because it makes me believe in things like talking cats, invisibility suits, and happily ever after.
None of that is at all helpful, I know.
I tried to think of places where voice failed. The best example I can think of is one that greatly pains me: Rita Mae Brown. I'm a devoted fan of the writer herself, and of her work. I love her SneakyPie books a LOT. But what drives me to distraction is when her own voice creeps in to the story. And by her own voice, I mean that she has her characters most often the animals (yes they talk...but only to each other) voice opinions about politics and the human condition that I know for a stone cold fact are the opinions of Ms. Brown. Ms. Brown is venting her spleen in feline dialogue and it stops the story cold.
I love those books, but I skip over the section where the cat discusses economics. I can suspend my disbelief that cats can talk; I lose it when the cats pontificate on the world beyond their ken.
I think you can tell when voice slips or is inconsistent by comments like "I didn't believe this." If I can believe in talking cats, I can believe pretty much anything; if I don't it means it doesn't fit with the world you've created for me.