Has anyone used the tommee tippee pump and go storage bags and bottles for pumping/breastfeeding ? I am going to register for baby gifts this Saturday and I am thinking about registering for this. I would like feedback on the tommee tippee pump and go starter set that comes with storage bags, bottles and warmer. The storage bags fit into their bottles with a nipple that screws onto the bag so there is no need to transfer milk to a separate bottle. The set also comes with a warmer to defrost the bags. It's kinda pricey and just would like some feedback from you all. I'm not sure about how well the bags store since they are not as flat as other bags. Also wondering if there is any issue with air when feeding the baby from these bags.