Over the past 10 years, I have purchased two UPS( Un interrupted power supply). One was a 500vA "APC" brand marketed by Wipro(no introductions needed) and the other is a 1000vA "Powersafe" brand manufactured by Kunhar Peripherals Pvt. Ltd. - a Mumbai based company.
Based on my observations, here is a simple test I have devised that you too can use to ensure you get what you pay for:
a) Ask the dealer to connect the UPS to a power point and connect the output to a bulb/desk lamp/computer or any other device that needs power to run.
b) Manually switch off the power from the power point.
c) Note the result.
d) If the UPS has protection for a telephone line, ask the dealer to connect the incoming line to the UPS and outgoing line from the UPS to the telephone instrument.
e) Ask a friend to dial the dealer’s phone(the one that is now connected to the UPS).
f) While talking on the phone, switch off the power supply to the ups.(The UPS should be "on" before your friend dials the number)
Here’s what I found:
In the case of "Powersafe" brand of UPS, it momentarily trips the device to which it is providing the output. In other words, if the device was a computer, it would have rebooted. Now the reason anyone would think of buying a UPS is to avoid exactly that kind of situation.
Note please: "Powersafe" brand of UPS does not trip the connected device if the power goes off on its own. Problem only happens if you manually switch off the power(think of an electrician working somewhere switching off the mains)
In the case of APC brand of UPS, I found that it fully trips the telephone line. So if you get your internet via the telephone line, each time you enter your credit card details when buying something online you need to pray the light does not go off before the transaction is fully completed. Alternatively, if you feel reasonably safe you can choose to not route the telephone line via the UPS.
Other than the above issues, both UPS seemed to function as intended. In conclusion, although far from perfect, the APC brand seems to be technologically superior to the "Powersafe" brand. Also, so far I did not have reason to call either service centers so I cannot comment of their after-sales-service.