I brought a New Geyser from JV Electricals, Bangalore. They suggested me to buy Shivalik Geyser which has a Copper Tank and I have been using it from the past 4 months and It has been working very well and water is heating up soon and not a problem from the Geyser and the JV also gave very good advice and support.
I would suggest people to buy products from JV ELectricals, Bangalore. Here is their Website- https://jvelectric.co.in!