No, as per available information there are no extra side effects of stainless steel bottles, in fact they are generally free from some of the Chemicals that may be added in plastic bottles, the only problem is that I can see that they are heavy and that they may be more expensive and cannot be used in a microwave for heating and sterilization purposes

Do NOT use a bottle for giving feeds,expressed or top. Though tedious,spoon and katori feeding is much more hygienic.