The hardcover version is the same as the softcover version
except for the copyright page (the cover art is the same ---
ignore the weird cover shown on lulu.com).
The hardcover version is available only from lulu.com,
because to make it available worldwide I would need to get
another ISBN and the book would be sold at the retail price
(even by lulu.com), which is twice the wholesale price, and
so the price would be close to 40 USD.
Ordering from lulu.com is slow, even for those in the
US, since it takes them about 10 days to make the book.
The quality of the hardback is quite good --- rugged
cover, and the binding appears to be sown and of good quality
--- and the book lays flat(!).
Certainly, if you are recommending the book to a
library, you should suggest they get the hardcover version.
to go to the book on lulu (or go directly to lulu.com and
search for Elliptic Curves).