Which Size of iPad Do You Like?

Which size of iPad do you like? 
I want to buy one by following your suggestions, please send me your suggestion, appreciate it.

Some people choose the smaller one as it’s convenient to take it in the bag, some people choose the newest one as it’s perfect to watch a HD video or movie. Which one will you choose?

The newest iPad is 12.9 inch. 

iPad Air 2

iPad Mini 4

I’m in Bangladesh, my friend told me I can buy it with USGo_Buy, it seems it’s very cheap to use this service buy things from USA, nearly 80% off shipping price. She always buys shoes with it. 
http://www.usgobuy.com/en/us-online-shops/apple.html

Please let me know if you have other good recommendations where I buy it.

I appreciate if you can give me some suggestions