There are a few parts of this story that bug me but thats bound to happen in a YA. I didn't love it but I didn't hate it either. There's one plot twist that I approve of...

The prince getting turned into a dark fiend

. and an other plot twist that was annoying

Mal being the third amplifier

The ending was okay... I guess.

They live not that happily ever after. Sad they don't have their powers? Running an orphanage? They just resign to being boring for the rest of time? Not the best ending for a fantasy. Would have been more interesting if Mal was dead or Alina. Or maybe if there was more questions into if she had survived the last battle. Just seemed a little too clean is what I'm saying.