Snapchat, I have been using this app from 20 momths now. Its a great app and slowly is gaining its popularity in India. Still many people dont use this app due to the difficulties they face in understanding this app.
Even I faced the difficulties in the starting, later it was easy.
It eats your mobiles Ram a lot, drains your battery but still it is a must have app in your phone because of the features it has like filters, stories and much more.
Storing directly to the camera roll would have been better, introducing memories was a drawback in this app.
Overall a must have app.