Best brand ensures quality, efficiency and good after sales service. From so many brands here comes the best ones- AO smith, Havells, Crompton, Bajaj , Racold, American Microni, V-Guard, and Kenstar.  They offer geysers with capacity from 10L-35 L. They are available in Amazon or Flipkart. Some of them provide free installation. Even if it is paid they are always better than a calling local plumber.