January Jones was criticized by one of the creators of Lost, Damien Lindelof; who, upon seeing the movie, tweeted:
“Emma Frost’s THREE mutant powers: Telepathy, Transformation to Solid Diamond and last but not least, Sucking at Acting.”
January Jones rose to fame in the last few years thanks to her breakout roll in Mad Men (which also stars Christina Hendricks).
I’m not a good judge of acting, myself. To me it’s either fine, or awful, and I don’t think Jones was awful.