I will revise my opinion slightly (Post 2)
OCR or other errors do not bother me unduly unless really really common in a particular book.
But as with hamburgers, or furniture etc. I will tend to do business with a company providing a quality product at a good price.
If I know that company A makes good furniture and Company B, the chair legs tend to come off, well we know where I will shop.
But if there is only a slight quality difference and Company B's chairs are half of the price of company A's chairs, I will be seduced by the price difference.
So far I have only come across intolerable errors in PD books, which were free and was able to replace them with better OCR'd and formatted ones for the same price
Helen