Vicious was an entertaining read. Most of the characters were relatively enjoyable. Eli and Serena were particularly unpleasant but they were the main antagonists of this story so that tracks. I found it interesting that even though the writer was trying to portray everybody with a certain level of balance: Victor the antihero and Eli the misguided savior, we still experienced everything largely from Victor's point of view. Resulting in the reader sympathizing with Victor and casting Eli as the obvious villian. We also find out very little about Eli's backstory, which personally left me wanting. Eli just felt like a typical villian archetype because of it. All of his motives and personality condensed into his insidious goals. He was definitely less fleshed out than all of the other main characters.

Part one of the story was a little tedious to read because most of the exposition revealed in this part was covered in the blurb of the book. 
The general premise of the book is an intriguing one, super-powered individuals but the story only really focused on our two main characters Eli and Victor and their relationship; friends to enemies. So the rest of the EO world and the possible ramifications of said individuals are left largely unexplored.