Do you prefer a battery case or a power bank?

Smartphones are amazing — snappy computers right in our pockets, which can deliver connectivity, games, media, or produce a camera on demand. For all their awesome features, users will agree that smartphones still lack in one area — battery life. Truth be told, there's only so much battery the manufacturers can stuff inside an elegant smartphone's body, at least with today's technologies.

So, if you are an avid smartphone user or one that takes trips regularly, you probably have some sort of portable battery at the ready. There are two main choices to go for — a powerbank, which can get quite massive; or a battery case, which protects your phone while charging it and doesn't require you to remember that one extra item at all times — it's just connected to your smartphone.

So, which one of these do you use? Or are you yet to buy one?