I bought a 800VA APC inverter with the batteries and trolley about 2.5 years ago. This inverter continuously overcharges the supplied Amco batteries and they were replaced 14 months ago. In spite of continuously complaining that the batteries were getting dry every week(because of the overcharging), APC or its service partner - Laser Systems in hyderabad did not repair the inverter. They kept blaming the batteries that were supplied by them!
Laser Systems in Hyderabad is the worst service provider that I have ever dealt with. Their staff especially the ones who take the complaints are very rude and least interested in registering the complaint. After repeated complaints to APC, their "Escalation" team in Bangalore got involved. Even the "Escalation" team is highly unresponsive inspite of repeated phone calls. Till date, no one has visited to take a look at the inverter.
It is a big mistake to buy APC products. They may have good technology, but they do not back it up with service. If you are in the market looking to buy inverters go for Sukam/Microtek or any other brand but APC - you are likely to get a slightly better service in case things go wrong with the inverter.
Update: 01 June 2012
My father had also bought an APC 1KVA Inverter about 3.5 years ago. The battery over charging problem persisted even with this model and we had to change 2 sets of batteries till now. Lately, it has stopped charging the batteries. I took it to the APC service center in Secunderabad. I mentioned to the technician there that the unit does not charge the battery. He said he will check and I could see that he was connecting to his batteries and some load while I was waiting. After a few minutes, he came back and told me "Sir, the Inverter is not charging the batteries. I will open and check if there is something wrong with the board". I again waited for about 15-20 minutes and could see that the technician was frantically searching various drawers in the room. After a while, he comes and tells me "Sir, we do not have the right screw driver to open the unit"! I gave him a piece of my mind and left after he promised he would get back to me on the cost to repair the unit. Throughout the day, the service center was trying to convince me to go for a buy back and get a new inverter from them. That was the last thing I would do - go for another APC inverter!
Later, in the evening, I was again called and told that "The problem with the inverter is that it is not charging the battery and that there is a problem in the board and shall cost Rs 3, 500 to replace." They charged me Rs 200 to just tell me this - I doubt if they really opened the unit to diagnose the problem. I got the inverter back home and am now planning to get a Su-Kam inverter. The APC inverter is now waiting for the Raddi-wala!