I really enjoyed this a lot. Sia was a likeable character and believable in her reactions to things and the position she was put in. The world building was interesting and original and we'll fleshed out. The male characters were great as well, all different and equally likeable.
I have two minor quibbles, however. Firstly, there was a bit too much of the lengthy description of the fake physics side of the aether and Sia learning to use her powers. It was interesting, but I think it just went on a bit too much.
Secondly, it is advertised as a RH book, and there are elements of this in the first book, and a set up for more to come in the future, potentially. I am fairly new to the RH genre, and surprised I've enjoyed it as much as I have, as I loathe love triangles, or books where there are multiple love interests and angst and the girl torn between them all. I just find it rarely well done and more of a lazy writing tactic to create tension for the main pair. I think this is why I've come to enjoy RH books so much in the last few weeks, as this isn't an issue!
Thankfully, the RH elements have none of the postering or jealousy/rivalry nonsense in this book. However, Sia is very intimatly and deeply romantically involved with one of the men, who she clearly places above the rest, whereas there have been a couple.of kisses with one other and nothing from the rest. That niggled at me a bit, as I think RH only works (maybe just for me anyway) when all of the partners are equal in the girls affections, both physically and emotionally. This idea that she can fool around with the others, but only if she likes him the best, hints that there will always be that imbalance, even if the rest of them become more intimate with Sia. Also, Nick's just a little too perfect, I sort of wanted him to bit a bit edgier.
However, I have no idea where the RH will go, and Nick is very open about having no issues with the possibility, so maybe the feelings for the others will grow equally strong.
If you like your urban fantasy with interesting world building, a likeable heroine, a group of attractive and engaging men, all of whom are equally likeable (give Luke a chance, he'll grow on you!) with a strong, but in no way overpowering, romantic element, then I can imagine you'd love this book!