I'd say it's good. The manga has a complex and engaging storyline that keeps you hooked. The art style is also distinctive and adds to the appeal. But be prepared for some intense and emotional moments.
Lucy does survive. The manga's ending provides a resolution that leaves her with a chance at a new beginning. There are various factors and plot developments that contribute to her survival.
Definitely not a happy ending. The manga takes some dark turns and doesn't wrap up in a traditional cheerful way. It's more thought-provoking and emotionally charged than just happy.