All formulas are definitely not the same despite what people say, even it they have the same ingredients on the tin. Aptamil and Cow and Gate both have prebiotics in them which are supposed to reduce constipation whilst SMA does not which might explain why it constipates some babies (not all though). On the negative side though Aptamil gives babies runny, sometimes explosive poo but does tend to reduce constipation! Have never used C and G so can't comment on that. And re the Aptamil Cow and Gate thing - they are made by the same company (Nutricia) and in the same factory I believe. My friends rang Aptamil and asked them the difference and they said that they use a different herd of cows for each and that the ingredients are in slightly different proportions. If you're not sure, how about buying a ready made carton of each and seeing which one you or your LO prefer. It really does seem to depend on the baby.