My opinion did not change – I think with the title I was expecting someone unlikeable. I do enjoy books with unreliable narrators, so I believe my experience with that genre prepared me. I normally find characters are complex, flawed, and neither all good/bad.
She was definitely unlikeable but had some sort of charm or charisma that meant you were pulled along for the ride. I felt bad for her at the end, even though she was quite a nasty character. As it was from her point of view, sympathy was really well built. I would hate to be friends with her, much worse be her enemy, but she made for a fascinating character.