I loved this book and read it the day it came out, then promptly reread it. Lothaire is evil, intense, selfish, and arrogant. I wouldn't change him and was so glad Kresley Cole kept him true to the character we've seen throughout several other IAD books. (He was especially ridiculously awesome in Dreams of a Dark Warrior.) Ahem. I tend to prefer nice guys as heroes, but Lothaire is a notable exception. As he reacts, repeatedly to Elizabeth by saying, "Too much!", it is that same crazy, in-your-face, I-know-you-want-me that apparently did it for me too. He is entirely too much. Hulk of the vampires, indeed.
When I read the first three chapters that were released early I was really surprised by Cole's decision to pair him with Elizabeth, a human, as his Bride. I had expected another alpha-female of the Lore. But, I grew to love her and appreciate her intelligence, bravery, and just how different she was as a character. She's definitely in his orbit, but she gives it right back to him too. (She does the same with Regin later in the book, which is quite impressive.) And, seriously, his nicknames for her were killing me. So sexy.
As others have commented, the scenes with Nix were poignant and humanizing for both her and Lothaire. I've always enjoyed Nix, but she can have a deus-ex-machina quality to her and this was a nice change to see her as more of a character than a device.
Lothaire's treatment of Elizabeth is deplorable and other reviewers have appropriately questioned whether he earned her forgiveness. To me, he did. I would expect him to help Balery (the former Hag in the basement) find her HEA as a little extra penance though.