I never actually thought about asking for pre-readers on here and as a result, all my pre-readers are either related to me or close friends, and we know what a good pointer that will give to how good the book is. About all I could rely on from them was the fact that all of them picked it up and couldn't put it down, including my sister who was due to make a trip in three days, and nearly had no time to pack!
So maybe I'll try this, too.
The down side of having your relatives as pre-readers, of course, is that you end up with no market!