I've used the Managed Recoil in 7mm-08 for my boys at 10 years old during the youth hunt. It makes a difference in terms of felt recoil and their confidence for bench shooting. My oldest took a doe at 120 yards his first year, and it performed well on an almost perfect shot. Last year, my twins both used it. One took a spiker at 70 yards, and there was almost no external blood. Shot was back just a bit, catching some lungs and liver, but luckily it went down in the field. My other one hit a doe broadside at 50 yards. She was hit hard, but probably back just a little bit. No blood, and we never found her.
I have some in .270 that my oldest son used last year, but was holding out for a buck and didn't get the chance so I don't know how that performs in the field. I'll let them shoot up the boxes I have from the bench, but will re-zero and use "regular" ammo for all of them to hunt this fall.