I'm so glad you all like your back packs. I had a great one with my oldest and I remember it working very well. Then I bought the little puppy with my 2nd. She used it one time at Disneyland. Literally within 5 minutes of having it on she tried to run and got whipped back by the leash, fell over smacking her head on the curb. Fortunately she didn't bleed and she was fine but now she just uses it as a toy when she wants to pretend she is a puppy. I think the reason I like the one my older child had was because the leash part was more elasticy so she could run but not very fast and when we pulled on the leash it didn't jerk her towards us.