4.5 stars. 
 Sanderson knocks it out of the park again for me. Though very different from The Rithmatist this book has a lot going for it. 
 Some people will find this book more accessible, because even though Sanderson still builds his world, it's much subtler. The book is fast paced and full of pulse pounding action. In fact, I ended up finishing it by accident. I had only intended to read the next section, but got caught up in everything. 
 This twist on "superheroes" reminded me a lot of Vicious in places. Yes, the Epics are evil, but the Reckoners aren't exactly good either. David is obsessed with revenge. Some of the team has questionable morality. At least two of them are hiding massive secrets... 
 Steelheart ends up being more of a mystery book than you'd expect. The central plot is trying to take Steelheart down. But in order to do that, the Reckoners must find his weakness--every Epic has them, and they're often bizarre. As the plot unspools, you start to construct your own theories about what's going on and how Steelheart might finally be defeated. And I have to admit, I guessed wrong! 
 Still, being wrong didn't detract from the enjoyment of that final epic showdown at the end of the book. There were several plot twists that were incredibly shocking. I didn't see them coming at all! 
 That said, not a perfect book for me. This is very plot driven instead of character driven. Which is fine, since the plot is awesome, but David in particular didn't really do anything for me. I mean, I certainly understood him as a character, but I never connected with him. And his ridiculous insta-crush on one of the female Reckoners was obnoxious. 
 But the same goes for most of the main Reckoners cast. They all definitely had implied Pasts, capital P necessary, but they were all still relatively two-dimensional. 
 I like to have some investment in my cast of characters. I want to feel like I know them. (view spoiler)[There was a major character death near the end of the book that didn't make me tear up even a little bit. (hide spoiler)] I felt fairly detached from everyone. 
 Still. This was a great book. I'm fast becoming a Sanderson fan. And if you're looking to jump into his work but are intimidated by the thought of his complex worldbuilding, I'd start here. (I love complex worldbuilding myself, so I feel like if I had to rank them, I liked The Rithmatist better than Steelheart, but I'm definitely in for book 2.)