This isnt a discussion on who is the better skater, which I think 99% would agree is Kostner. However who has had the better career of the two. Comparing them Ando has 1 more World title. However outside her 2 World title, has only 1 World bronze. Kostner has 1 World title, but 5 World medals overall. Kostner has won the Grand Prix final, and medalled at the somewhat prestigious event 3 times. Ando has never won it and only medalled once. Difficult to compare their European and Four Continent results given the weaker European field and Ando not even frequently skating at 4CCs. Neither has a strong Olympic result.
So basically it is Kostner`s 3 additional non gold World medals, and superior Grand Prix final results vs Ando`s 1 additional World title. I would give Kostner the slight edge for better career, as I just find with her large total of World medals spread out over a very long time, many European titles (even though Ando could probably have done nearly as well), and strong performances in the Grand Prix final her career is slightly more complete, but it is close and could easily go to Ando given her extra World title. If Kostner does the expected and medals in Sochi she is easily ahead.