Urban travel powerbank
I'm trying to decide between the Anker 737 and an Anker Nano power bank.
I mainly want something easy to carry in a small shoulder bag or backpack for everyday use, travel, beach days, etc. I occasionally end up charging 2–3 phones (mine plus friends'), but I don't need mainly laptop charging (only tablet but rarely).
I prefer something lighter and cheaper if possible, but I also don't want to regret getting too little capacity. Is the 737 worth the extra size, weight, and cost, or is the Nano the better choice for this kind of use?
Which one would you pick and why?