@
gastan,
I think I understand what you mean.
Now, I have found that those books are easy to spot *before* you commit to reading them.
Most places let you read the first chapter or two, to get a feel for if you'd like it. DON'T keep reading if you can't take the grammatical torture evident in the first chapter!
But to be honest,
I find most of my books through recommendations.
If someone who I trust liked the book, I am confident the grammar is professional, and I don't bother to find out if it is self-published.