There are 3 types of UPS units available for home use: Standby (cheapest, most common), Line interactive (mid range), Online (high end).
I would recommend you to watch this short video for the simplest and clearest explanation of the concepts differentiating these types of UPS:
Since you are in Bangalore, I would recommend you to choose Line Interactive or Online UPS due to heavy fluctuations in the city. Alternatively if you get a Standby UPS, you can pair it with stabilizers for sensitive equipment such as computer, fridge and AC. In bangalore there are UPS+battery dealers in every neighbourhood, if you are not comfortable with troubleshooting and maintaining the UPS system, I would advise you to pick a dealer nearest to you (who has good reviews on google maps). Ask them about their service response time and service warranty from their side (besides brand warranty). If you can manage things on your own, you might save 5-10% by picking up a UPS unit from the computer market in bangalore (SP Road). You can negotiate with them for an installation service, but don't expect service calls from them during breakdown. Computer market shops are strictly transactional.
As for brands, I've been a loyal Amaron customer for more than 25 years for car batteries and 6 years for UPS tall tubular battery. In these 6 years, I haven't even had to top up the distilled water yet. I'm currently using a Microtek Standby UPS, but I'm looking to upgrade to an Online APC UPS in the near future. Try talking to your neighbours for a realistic picture of how different brands perform and how is the service response time in your area. Microtek service has been very good for me, engineer arrived in 1-3 days and problem solved on-site in an hour, but I don't like the fact that it has blown up twice in 6 years. Ideally I would like the UPS to be as reliable as my Amaron batteries, requiring no service visits at all. Which is why I'm looking to spend a little more for my Online UPS purchase.
