Aquaguard may be a good brand, not necessarily all the products are good.
I was using KENT and happy without any problems, though had some limitations. service is prefect and you know exactly what your expenses are depending upon use and obviously no electricity charges. Then comes Auqaguard sales representative and he was good to convince us with the pros and cons of Aquaguard and finally I bought a latest product, MAGNA NXT, which was my mistake. Always buy only a tried and tested product in the market. or you will become the victim to test their products at your cost. And when it comes to service, its 15 TO 30 days . So before you choose your product, do a very good market research, especially regarding service. Mind you, operation cost wise its never cheaper than KENT and you dont know what you next(regular) service cost will be, of course unless you take an AMC.