My Opinion: Both-I like how shiny the older cover is, but I also think the newer one's background represents the idea behind the book a lot better.
The Future of Us by Jay Asher and Carolyn Mackler
My Opinion: Older-I think the background looks a lot cooler, and it's less plain than the new cover.
My Opinion: Older- The image on the older cover makes the book look more interesting to me and it also hints more at what it's about.
Fairytale Retellings Series by Jackson Pearce