This is both a loaded question, and an attempt to compare apples and oranges. Loaded, because Sarah had 7 years to establish a beloved character and an entire universe in which to operate, whereas Kristy had only 90 minutes in a less than first rate movie, somewhat indifferently directed, and based on a poor interpretation of the original script. Given what she had to work with, Kristy did an excellent job.
Reverse the two roles, put Sarah in the movie as shot, and Kristy in the series as produced, and I have no doubt that Sarah would draw the short straw.