In short: Shades of Earth by Beth Revis was an intense and thrilling finale to an incredibly exciting and entertaining series. 
 FREX, Shades of Earth was INTENSE. The action picks up right where it left off in A Million Suns and does not let up. As with Across the Universe and A Million Suns, Shades of Earth is very fast paced and that, along with short chapters that all end in mini cliffhangers, will ensure that you speed through the story quickly. Shades of Earth is a fantastic conclusion to an incredibly fun and entertaining series. The stakes are raised to a seemingly impossibly high amount. I've come to care for Elder and Amy so much that I was all the more tense while reading, just hoping they would make it through the series okay. Chaos, lies, and murder abound in this absolutely thrilling finale. 
 Probably one of my favourite things about the Across the Universe Trilogy is the frequency of surprising and shocking twists in the plot. I'm not exactly sure how she does it, but just when you think there couldn't possibly be any secrets left to reveal in this world - BAM - Beth Revis hits you with a whopper that leaves you reeling and in need of a moment to gather your wits about you in the wake of all that craziness. Seemingly in the next moment - BAM - comes another blow, another crazy surprise twist that had never occurred to you and has you literally gasping out loud. Again and again and again. This is what makes this series so FUN and I LOVE it. 
 Those who have read Across the Universe and A Million Suns know that Beth Revis is a master of world building and Shades of Earth is no exception - it is always intriguing and never bogged down with too many details that would bore. What's more, she's set up an amazing base for if she ever chose to continue writing books set in this world. She could write a whole new trilogy with how much is left to discover! And it would be just as exciting and intriguing as the world building in this trilogy, I'm sure! And I would absolutely need to be first in line to get it. 
 Now, I can't say that Shades of Earth is absolutely perfect - I noticed a number of plot holes and scientific inaccuracies - but I could really care less. In my mind, those minor mistakes take a back seat to the real meat of the novel. Shades of Earth, and indeed the entire trilogy on a whole, is exciting, surprising, and entertaining. It is an awesome sci fi, and insane thriller, and a deep felt romance. If you haven't read this trilogy yet, then what the heck are you waiting for?