It's been awhile since I've read Gravity, but I knew I really liked it as a whole and was definitely intrigued by this alien race and the struggle between them and the humans. As with the first book, this took me a minute to get into. Not that I didn't like the first half, because it interesting learning about Loge, but nothing really happens. The latter half though, is excellent and I was definitely glued to the pages. 
 Ari took a minute to grow on me this time around. She's doesn't start off as tough as she was back on Earth. It's understandable though, because she's now on Loge, and it takes a minute for her to adjust to her surroundings, the fact that she's part alien/Ancient now, and she is now challenged with a task that tests her strength and character. I think she was too in her head for the first half and it bugged me that she couldn't see the "bigger picture" quicker. I definitely liked how she stepped up and finally showed how tough she was in the latter half and you see that soldier side of her that I really liked. 
 Things with Ari and Jackson are strained for much of the book because of how he lied to her in Gravity. Trust me, I hate lying. No matter what the reason, I don't believe in lying. Period. Regardless, Ari should've come to terms faster and addressed the issues with Jackson better than what I saw. Jackson does deal with his own problems in this book, but I would've liked to see more of them, as a couple, handling their situation. Also, it bugged me how much Jackson kept from Ari. It gets to me when guys think they should hide things from their loved ones to protect them or something. I'm an advocate for treating your significant other as an equal, especially someone as tough as Ari. Some girls can't handle it, sure, but I think she could. But that's just my personal opinion on the matter. 
 I still adored Jackson at those moments when he let his guard down. You could really tell he cares for Ari deeply and there were quite a few moments that tugged at my heart because of him. 
 Also, two words: Jackson. Shower. 
 Enough said. 
 Anyways, Hover was a great sequel and I really like this world that Melissa created. I'm definitely going to check out Collide, the third book, to see how it all ends. If you enjoyed the first book, you'll love seeing the alien side of things this time around.