I use karbonn sparkle v recently.And I found that this phone is best under rs.4000.The feature given in this phone is nice.This phone performance is very good.This phone run with android kitkat, but google android one is given so the updates & security patches will be upto date.
Karbonn is not a popular company on the world.But at this phone can give a great challange to other company in the market , to launch budget phone with all feature.
This phone is work great & I am happy with the performance.The app & google security which is given in this phone, I really feel safe.