The books are worn rapidly after a single reading. For too long, holding a page may result in blurring of the words. It's definitely not a paperback from Germany comparable, because the paper is much thinner and lower quality.
The cardboard slipcase is as cheap as unstable and it can be difficult to get the books back into the box.
For a one-time use of the books to the price history around Game of Thrones in the original language is zulesen perfectly okay, considering the price of German books.