I have giggle life (bought before baby was born). Supposed to fit at 8lbs... No way.
Now she's 15 lbs and I get a good fit. My girl has huge thighs and they seem to have a higher thigh cut than others (I also have kawaii, kushies and alvas).
If your child is skinny these are not for you. They don't have hip snaps which most styles have now (or at least the ones I have don't).
That being said; I like them best for fit and ease (no hip snap means one less snap for DH to complain about... lol).
I don't recommend buying them before baby.