The new Eldar codex is the first 6th edition codex I've purchased so far, and I have to say that the new hardback format is nice. The higher quality binding almost makes you forget about the crazy high price tag for these new books. I honestly didn't mind the old softbacks, especially after I had all of mine spiral-bound at kinkos, but at least the new hardbacks can lay open on their own just fine.
Anyway, moving on to the actual content of the book... there's some really nice entries, some overpriced/overcosted entries, and a lot of potential combinations that remain to be seen.