Lenovo P780 is going to give its buyers a most useful feature - which is the ability to function as a power bank, which none of the other handset offers. All you need to to is connect the phones using USB and OTG cable. The 4000 mAh colossal battery starts charging your friend's smartphone. You can simply reverse the cable connection to charge your phone using any other phone. I think this features would be somthing everyone wants to have; especially people who travels a lot.
I have written a review of Lenovo P780 on Saholic blog.
Lenovo P780 review