I am using Eureka Forbes Aquaguard i-Nova, for last 3 years approx. I have some comments to make about this product.
First the company follows a very aggressive marketing policy which some times force customer to buy their products. The problem with the marketing professional is that they do never mention about the hidden cost once you buy the product.
You need to go for a sort of mandatory service contract which will cost you around 1400 per year as the candle (the main part of the filtration unit requires an overhauling.) Apart from that you require to invest some major amount after certain amount of time in maintenance.
But you will never find the sales guys telling you all these things. I personally not happy with the service they are providing in the service contract.
I am also doubt full how much it really works as it is not feasible for us to do physical testing of the water. We have to believe the sales guys word and some awards that may have been given to the company.
If possible do a boiling of the water which probably is the best available solution.
Last word : Be very careful before falling a prey to this company