The greatest I've seen of her, so far, is her fist Giro win in 2011. I knew she could sprint, win from small break-away groups, win solo, win in the field, win on the track (don't forget, she is also an Olympic gold medalist on track), and ride well on mountain stages, but actually winning the hardest stage race in the women's peloton, the Giro Donne, was a revelation for me. She won 50% of the stages in 2011, including big mountain stages, not just bunch sprints, which she also did.
It wasn't just a one year fluke, she repeated that trick this year, winning 5 of 9 stages (56%, but that's inflated, 2011 edition had 10 stages).
That said, there's one thing she could improve: time trailing. She has won major time trails, but at the Olympics she had a total off-day and there are better time trailers in the women's peloton. But, hey, you got to leave some races for the competition, else they might quit demoralized and demotivated.