Breastmilk storage bottles vs disposable bags, which one is easier to use? Any brand to recommend?

Breastmilk storage is more time saving as no need to spend time washing and sterilise the them as compared to storage bottles. I used double zip lock to make sure the bag sealed up tightly and avoid any cross containmination in the freezer. http://www.autumnz.com/autumnz-double-ziplock-breastmilk-storage-bag-25-bags-12oz-p-7.html