IMHO - what your child learns and the learning skills he/she picks up in elementary are what your child builds the rest of their education off of. We happily sent our kid to private elementary knowing that she would go to public middle/high school, because the private elementary set her up for success down the road. Even in high school our daughter would comment that the Latin units in upper elementary were helping her in high school. My wife and I both commented multiple times how the private school made her a better learner which allowed her to get more out of high school.
Our mantra was, “every $1 spent in K-5 is worth $2 come college time”
Best of luck,
-S.F.