If you can, I'd be interested in how it came out. There were parts of the first book I enjoyed but I never picked up the second.
I think I might have a bias against mixing vampires and superheroes.
Well, I finished
They Promised Me the Gun Wasn't Loaded Tuesday, flying on a business trip. I enjoyed it. I can say this to you, #Blue: if your main problem with the first book was mixing superheroes and the supernatural (vampires, werebeasts, ghosts, demons, etc.), then this book will disappoint you, because they're there in the mix. Of course, given the way the author's designed this universe (multiverse, really), that's going to be a factor in any book in this series.
However, that said, I think you'd enjoy this one a bit more than
All Those Explosions Were Someone Else's Fault for the simple reason that supernatural creatures, while present, play a much smaller role in this book. Ninety-Nine is the main character this time around (in fact, the other three superheroines on her new team are not in the vast majority of the book), and it deals primarily with her interactions with a different superhero group led by a guy calling himself Robin Hood. It turns out that just because superheroes are powered by the Light (as opposed to the supernatural being powered by the Dark), gaining Light-infused powers doesn't necessarily mean that you'll be a goody two shoes fighting for truth, justice, and the Canadian way. (The book takes place in Canada - it's a Canadian author and in his books, anything of any consequence always takes place in Canada.) Robin Hood and his Merry Men are a good example: while they purport to steal from the rich (which in this universe means invariably Darklings) and give to the poor, nobody knows for sure what he actually does with the money he steals, and he's got some rather questionable people working for him.
Anyway, an interesting plot (everybody's trying to get hold of a super-weapon very possibly created by Diamond, the supervillain Mad Genius from the first novel), some interesting takes on superheroes, and typically good characters, including a shakeup of the Ninety-Nine character. I wouldn't necessarily recommend you go out and pick this up, but if it's ever made available (like a library copy) and you feel like giving it a shot, I think you'll get some enjoyment out of it.
Johnathan