Babe Ruth will better prepare to adjust to the larger field. I am sure both leagues will have some benefit. Both talent levels should be equal as players are about the same ages. Remember, when a kid moves up to the larger field, so do all the rest of the kids in the league. I have had kids play Pony in the past and got a false sense of dimensions and they were pretty overwhelmed when they moved up. That can be said for L.L. to Babe Ruth. I would also look into the quality of the talent and the coaching and instruction for each in your area. Good luck.