We've been using follow on since 7 months, it's slightly thinner so easier to drink, perhaps better for transitioning to cow's milk. Also has slightly higher iron. I think my LO prefers it TBH.
I've been using it for my little girl as a slightly cheaper and was told it's the same as first and she's only having 2 bottles a day will use it till cows milk next month x
My health visitor told me to stay on stage one and not to go into the follow on due to the minerals?