Simple question. Which do colleges prefer?
Both.
The two are very often tightly linked. There was a study done, and you can determine person’s grades 85% by grit, 10% by IQ alone, and 5% other factors. There’s a ted talk about this somewhere on the web.
While grit is clearly important, a person who struggles with say Algebra is not going to master Calculus simply due to grit.
Grit influences grades.
GPA at most high schools are more due to grit, like most things in life. It’s only when you go to a higher level of education that smarts shows more.
Ha.
To answer OP’s question directly, since GPA in High School is a strong evidence of GRIT, colleges prefer to see good GPA. Many smart kids in high school who are lazy end up with lousy grades but with very high SAT/ACT scores. I know because I was one of them. For me, my GPA remained between 2.0 to 3.0 from high school to graduate school mainly because I quickly grasped basic concepts but was too lazy to study hard to grasp finer points.
Colleges like to see performance over potential. So grades. However, if you’ve gone through extenuating circumstances that you write about in your additional info, essays, or are in your recommendations, grit could be valued highly.