I was gonna write something meaningful, but the pretty dame sure provided the full low-down rounding up the subject matter. Cheers, P.
I think what is important here is not to offer too much text to the customer, he might get bored. On the other hand if your eBook is like 150 pages, try to separate it in 3 smaller books, than you clearly advertise like pay 1 get 2 for free. That way everyone is happy!