You would think that in book filled with archtypes and characters that were well written to be examples of what the author either admired or disdained, that Dagny would be a little one sided and not as dynamic as she is portrayed. The author did a brilliant job showing a woman who is both principled and flawed, a woman who strives to save everything she loves and starts an affair with a married man all at the same time. She is a woman who respects herself and knows what she has to offer to her company and other people in her life that she respects and admires. She is a woman who will not compromise her beliefs even when society seems to be falling apart around her.
Regardless of what an individual reader feels about the book or Ayn Rand herself, I would just say that this character is brilliantly done and one of the strongest women I've ever had the honor of reading about.