Let me first mention that breast milk is the best food for a baby and there can be no alternatives for the same. If feasible, you can express your breast milk and store it in the wall of your refrigerator door so that it can be brought to room temperature later and given to your child while you are not there. Most formula milks are cow milk based and hence hard for the child to digest. If breast milk cannot be procured, any baby formula would do, and I would not place any preference. Cerelac or nestum are not milk substitutes. They are cereal based and are supposed to be started after weaning the baby to semi solids at 6 months of age. Early weaning can be done at 4-5 months and it is not totally objectionable. But if you boil rice togehter with pulses and vegetables and give it in the mashed form to your child, it will be equally nutritious if not more and I would definitely prefer this to the formula. Flavours are for taste and are just a matter of personal preference and nothing else. I would prefer rice based formula (like nestum rice or cerelac rice) compared to wheat based formula (plain cerelac).