I've been using both Tripp Lite and APC for many years. The Tripp Lites all lasted about three times longer than the APCs. Tripp Lite is no longer available locally so I will be buying them online and I will no longer use APC.
APC are good UPS's. Much better than any of the others we have tried. They have long duration models that allow extra battery's to be added that can run as long as you need. They are designed to keep network and phone gear running during a blackout. But they are BIG and HEAVY. 19 inch rack size, 2 feet deep, 10 inches high, another 10 inches for each expansion battery. Take the batteries out before you try to move one. APC units cost a bit more than other brands, but I have found them to be better quality. All UPS batteries will wear out and need to be replaced after a few years. You might need to test the unit to detect the worn out battery. If you run fully automated, you might just be better off using a colo since they have redundant power and network. It doesnt do any good to have a ups if some jerk knocks down a telephone pole with your power, cable, dsl, etc on it.
That's a pretty straight forward set up. You might as well add your cable modem and router to the mix so you'll have internet when it goes down. I'd recommend a Smart UPS 1000. It would provide you power protetion, some run time and power filtering in case of surges, spikes and all sorts of other anomalies. The main advantage of the line interactive UPSs is that they output a sine wave, a lot of the standy UPS don't and it's not as good for the power supply. Also, don't forget that APC is pretty much the leader in the UPS market. I know there a lot of cheaper options now but I highly doubt they are anything as good or as reliable as an APC.
Original equipment batteries should be lasting between 3-5 years. However, the abuse they take shortens their life. If they don't get discharged completely very often they can last a long time. Sometimes people get shocked that their batteries don't last 3 years on a brand new unit with very few power outages. There is a simple explanation. When you bought the unit from your local convenience store, it's been sitting there for 1 year, thereby shortening the useful life of the battery, if not providing you a practically dead battery. It's very important to check the date of manufacture on unit you buy, you could be buying a unit with a dead or dying battery.
I have bought 6 APC units over the years. Four are still in service and 2 have failed. The two that have failed were the smart units. Of the 4 that are still working, 2 are smart 700 units. As for replacement batteries, I have found the cheap replacements from eBay last me as long as the high dollar replacements I bought a few years back. I generally get between 2 and 3 years out of batteries. The last 3 units I bought were used from eBay without batteries and those units have worked as well as new units at a fraction of the cost of new units.
I bought a APC smart UPS 700 11 years ago, Change its batteries twice already, not with original oem parts, just regular 3rd party parts works great.
I have two APC 1300-XS battery back-up systems. Both are about a year old and I haven't had any problems with them. We had a power outtage a few days ago and both worked perfectly.
The better batteries last 3-5 years. Do you think you might be getting a shorter life with yours because you're using the cheap batteries? Also, have you actually load tested the cheaper batteries? M
I have not had problems with APC. I test them once in a while to ensure they are still working as expected. I have the Smart UPS 1500 for my computer and monitor (overkill I know) I also have two additional Back-UPS ES 725 for my other hardware (ie: external drives, one floor lamp, etc)
I have bought many used units from these guys at great prices http://www.upsforless.com/ There were all refurbs, and came with new batteries. I was able to buy about 2x the power that I needed for each application so they have served me very, very well.