Quantum Collapse is perhaps the most comprehensive and well thought out concept for how people could get super powers and have those powers develop over time that I've ever seen. Rather than the old idea of getting irradiated in various ways, this concept expands on theoretical physics concepts like quantum foam, multiple universes and different versions of Earth and other planets within those universes. What happens to your character and others in this world if alternate versions of you vanish elswhere?
This game is not tied to any of the existing comic book publisher lines like DC, Marvel or Valiant, so you and your players are creating your own personal super hero universe using heroes and villains in these game supplements to Mutants and Masterminds RPG, and/or making up your own from scratch if you wish. You may find that you want to use the characters in this book first to get a handle on playing the game (they are statted out quite well in the back of the book) and because their designs, quirks and backstories are quite clever. Who says there aren't any new ideas for comic book heroes anymore? You'll get some good inspiration here. I personally especially like Captain Cajun. Character creation and leveling is detailed enough to make you feel like your PC is rather unique, yet without being so unweildy that you can't keep track of all your options and abilities. It's clear that the authors have played a lot of super hero RPGs and have figured out how to fix some of the issues that many of them have.
There's even groups, or leagues, if you will that your hero can join, some good, some evil and a whole mythology of alternate history set up that has a unique twist on what was 'really' behind some of the secret government projects before, during and after WWII. It's interesting stuff.
The artwork has that old school OSR vibe to it with characters who are not as polished and professional looking as in the big name comics, but who have a certain charm and personality to them that is sometimes lacking in those comic books. They are portrayed quite dynamically though, with great angles and perspectives, not as flat, stiff manequims. The concepts are clever and are explained with a sprinkling of dry wit that makes the book an engaging read rather than something to skim through.
Whether you are a long-time player of super hero RPGs, or giving one a try for the first time, this is worth getting.