I am writing this review after 1.5 years of use of this product.
Pro - Looks good, gives mineral water(Which is it's job)
Cons- 1. Maintenance is very high. Every time the technician comes, he will charge 250/- (for very minor work also). 2. For 1st one year, the service is free and they will change the SF which is outside the device. After the warranty period over, one one problem starts. The GKK1 consts around 22k which need to be changed within 1st year(or 4k liters). GKK2 should last upto 8k liters, but it goes off very fast, and you need to change it by paying 3750/- 3. No electricity, No water. (The water button works with electricity only)