To start with, this book has a serious tragic ending, one that normally would make me just give up on the series. However, the rest of the book was good enough that I did keep reading.

I quite liked the main character, Hope Corrigan aka Astra. The story is told in first person from her point of view, and she's a generally positive person. She makes rookie mistakes, but her team, her family, and her friends all support her and encourage her. At the start her parents are understandably worried about her becoming a superhero since it's a dangerous profession, but admit that they raised her to take responsibility, and in this case that does mean doing whatever she can to help.

And she's not the only one making mistakes and improving -- her team does it too as they're called on to deal with types of events they've never trained for. In general it's actually a pretty relentlessly positive book, despite the high body count among the general populace. Some of that is independent of her, but some is directly due to her influence. For example, after a fight with her one hero realizes that he's gotten too dark & jaded, and tries to reclaim some of his youthful idealism. And after another fight, she convinces a bad guy to get some help for his problems. Independent of her, multiple supervillains pitch in to help however they can after a massive disaster, and at least one - the one she worked with, of course - winds up becoming a hero.

One nice thing about this series is that, while there's certainly plenty of super-powered fighting, the team is actually built around Crisis Aid & Intervention. They might (and do) subdue supervillains who are posing a danger to the populace, but once the bad guy is subdued it's someone in law enforcement who takes them away.

I liked the relatively slow build of the romance. It did escalate pretty abruptly towards the end of the book, but there were extremely valid reasons for emotions to be running high. The power differential bothered me a little (he was a full-fledged hero, she was still technically a sidekick), but she was the one making all the moves, and he was the one interjecting caution and common sense. The age gap did bother me since it exceeded the "age /2 + 7" skeeviness rule, but since there's emphatically no sex, and there was a catalyzing event, I was okay with it and willing to see where it went in the next book, once the adrenaline wore off.

But the ending... several important characters, people she's actively friends with and we've seen a lot of in the book, die. Completely dead, not coming back. The book ends with her grieving, and crying in the arms of her church's priest. (She's Catholic, it comes up regularly.)