I have got a 15 Liter BAJAJ water heater at my house. The water heats up very fast(Probably within Twelve to Fifteen mins). The problem I face with taht: It not holding the hot water for longer duration. The Heat insulation system of BAJAJ water heaters are not good enough.
Prior to that I used to stay in a rented flat, where the house owner had fitted a water heater of some local vendor which was having a capacity of 25 liters. That was heaving a very good heat insulation. If I heat the water in the morning I could still used to gat hot/warm water till late in the night(I used to get warm water even after 12 hours without switching on the power supply). This water heater also used to take the same time(Around fifteen mins for hot water).
I really do not remaber the model & manufacture of the water heater. Also I dont have much idea about the gargons the sales guy uses at the time of marketing. As an end user I would like to suggest if any one is planning for a new water heater he/she must consider the following things:
The average power consumption.
The storing capacity( which will suit bet to your needs).
The eclectrical insulation.
The thermal insulation.