I am using the Aquaguard Classic past 10 and 1/2 yrs without major problems. When we constructed our house and shifted, we had only our borewell water for drinking. Though it was certified potable, we decided to install a water purifier as it is more convenient and safe than boiling. We continued with it after getting municipal water connection.
I find the working very satisfactory. The quality of the water is good. All my relatives who come on visit from US drink the water without hesitation and never complained of falling sick because of the water.
I had good after sales service for a few years. For a year, there were delays in attending the problems by the service people. But, past 5 years, the service has improved a lot. They take the complaint and attend to it at the earliest possible, most of the time in a day or two. The service persons are polite and co-operative. As we are working people, they come either on a sunday or around the time requested by us.
I feel that a lot depends on us too. The service people are trained and educated persons. We must respect them and instead of being rude, be firm while treating them/registering our complaint. Understand even they might be overworked. So, no point in adding to their woes by showing our off our ego!