DS: My son has a mild preference for me (I do his bedtime and school dropoff/pickup).

DD: My daughter has a medium-strength preference for Mrs. Bee (she does her bedtime and dropoff/pickup).

We tried switching dropoff/pickups, but my daughter wasn't listening as well to me as she did to her mom. So we switched back, and it's been going well! We've both been making a big effort to spend time with both kids outside of dropoff/pickups/bedtime. I think it's working, as the kids' preference is pretty minimal these days!