We're still using this at 16 pounds for my tall baby. The leg holes are pretty big so would probably not work great for skinny skinny legs but we had no leaks. Born 8 pounds and worn from the first week.
I had never cloth diapered a newborn before and I bought this cover to use over prefolds on my newborn twins. The hook and loop is very strong and I haven't had any leaks. The fit is good on my twins. However, I didn't start using it until they were 2 weeks old and both over 8 lbs. I still had to overlap the tabs completely. I do not see how this cover could possibly fit a 5 lb baby as it claims to, but its still a great cover.