From day one the Rocket Bottoms NB fit the best out of the two AIOs. The umbilical snap down kept the diaper out of the way of his stump. I enjoyed quick diaper changes with the Rocket Bottoms NB and they didn't leak as long as they were changed every 3-4 hours. Plus they were trim which meant his 3mos onesies fit very well. By about 4wks however the Rocket Bottoms NB were starting to get tight and they leaked almost every time. There are two snaps side by side on each wing and I think the diaper performed better when we could comfortably snap both on each side. I finally retired them all by 6wks.
In contrast, I wasn't impressed with the GroVia NB AIO from the beginning. The top edge rubbed against his umbilical stump so I waited until he was at least 2 weeks old to start using them. They leaked and I struggled to get a good fit. You can tell from the photos that we actually tried a tighter fit around the waist and snapping down the rise at 4 wks in comparison to 3wks. Nothing seemed to change the fact that they needed to be changed every couple hours though. Regardless they seemed to have a decent fit at 6 weeks old even with the extra room offered by the snap down rise but I retired them anyway due to frequent leaks.