What is up with people copying the Twilight format? This book was almost exactly the same. The only difference, and why I was reading it to begin with, was a steampunk flair. I liked that, though I didn't think it was handled adeptly. It was like the author had never had any mechanical experience before.
Otherwise, let's look at the similarities:
Girl with unique powers-Bella has the ability to not be bent by the powerful Vampire Roman people (Venturi?), Tessa has the ability to "Change" and yet not be a conventional warlock and no one knows why.
Love triangle-These books are HARDLY the first ones to exploit a love triangle, they just seem to do it so poorly. In both books there is the brooding handsome one with some secret buried deep down who alternately loves and scorns the heroine. The other guy is much nicer and more constant, though also magically different (werewolf and demon blood addict [unfortunately I am not making that up]). Despite the fact that everyone is warning the heroine that the brooding handsome guy isn't good for her, the heroine is more attracted to him than the nicer, safer guy.
Predictable plot-Okay, so let's say you have the two elements above, you can still redeem yourself with a really good plot. Both Twilight and Infernal Devices have "twists" that you can see a mile away. Then they belabor the point by explaining the "twists" over and over.
Group of people to make up a "family"-Twilight has the Cullen's and all the "siblings" in that group. Infernal Devices has The Institute with all the Shadowhunter minors.
Then of course there are the mythical elements, all the werewolves, vampires, etc. I'm disappointed. I had heard such good things. I can't make it through this series like I pulled through Twilight. Speaking of series, I did finish the Hunger Games series and I'll update you on my thoughts on that series soon.