Actually, I have read a book by shamboosie(a weird name, I know) and he is a professional hair stylist (20 years) and he mentioned that no lye perms dry hair and leave mineral deposits.
I'm not sure about whether lye keeps hair straighter longer.
That mans book is one of the greatest hair care books for african american women (relaxed, natural, weave, etc...) I've ever read.
I really need to buy that book.