I really like how it expands on the blend of rock music and high fantasy themes seen in Queen I and since by that point, Queen had a better grasp of the kind of style they were going for so they were able to perfect the formula. Queen has made masterpieces but, Queen II isn't just a masterpiece, it is perfection in it's purest form. In my opinion, there is no part of Queen II that isn't good. Every single song on it from the Procession all the way to Seven Seas Of Rhye is excellent. Queen II captures everything I love about Queen and music in general.
In short this album isn't just an album, it's an ethereal experience that makes you feel like you are transcending from your human form and into a realm of pure bliss.