It really depends on what she's going to be studying.
I grew up in Virginia, have 2 parents who are Purdue grads (my father has BS, MS, and PhD all from Purdue's school of Engineering), and I went to IU (Purdue's rival).
Purdue is an EXCELLENT school for engineering, agriculture, and some sciences. They're not as well known for their liberal arts, but overall, it's an excellent education.
W. Lafayette isn't a bad college town and has good amenities (plus being closer to home). The sports teams are excellent most years - yes, it's hard for me to say that as a Hoosier fan, and Indianapolis/Chicago are both very close driving distance.
I know less about Georgia Tech but enough to know it's also a good school.
Some food for thought I wish I'd considered as a high school student making a college choice: I went 650 miles from home for college. I couldn't afford to leave and go home more than major school breaks (Thanksgiving, Winter, Spring, Summer). It was hard to be on campus alone sometimes, and wasn't practical to spend an entire weekend driving.
Purdue is certainly closer to home, but I think she'll do great either way.
I'd recommend basing it upon the academic program, how she feels on campus (you know when it's the right fit for you) and how she'll manage being further from home.