I use 奶瓶 as primary storage media and 儲奶袋 as backup.
The 儲奶袋 I used is Gerber. It has zipper seal which I think is quite good. But it is expensive that it costs about 2 dollars each. My husband heard from his friend that Jusco is the cheapest. I use a bag for each pump. So if I pump 3 times a day, I need 3 bags a day.
Since my milk volume is small, I use the 4 oz 奶瓶 which I think is also small enough for storage. Also save place. Sometime ago I buy it from Mannings when it is under promotion. It cost only 7.x dollars each jar.