I've tried a number of UPS units for numerous small business installations, as well as my own home systems and have yet to find a reliable brand. Some units last for years, other units of the same make/model end up burning out in 2 months. Not looking for the high-end here, but what brands/models have others found that work well consistently for small scale applications?
(Small scale being 1-3 servers, router and a couple of switches)
It may be the 'pat' answer, but I've had great experience with APC products.
I have had good luck with Tripplite, but APC is fine too.
I reply on APC. They usually last years, the replaceable batteries (RBCs) come with prepaid shipping labels for old battery disposal, and they offer a trade-up discount, again shipping prepaid.
I only use the Smart UPS in situations where I want the extra analysis, mostly relying on the BackUPS line, like the RS900, load needs-dependent.
We use a number of 'Powerware' ups's that have always worked well for us (available in Australia, not sure where else) but the most useful thing I can say about UPS's is
Learn how to change the batteries. Its not a hard task, you can get replacements quite cheap if you have a local battery store (cheap as in $30AUD, not cheap as in cheap-noname brand junk)
This will ensure your UPS's are usable and even retirable when they've done their 3 years of office work. Add new batteries, sell at a little above battery cost to your staff, saves getting rid of them on ebay or dumping them and your staff then have surge protection and backups for home :-)
APC or PowerWare. PowerWare has great hardware. Only thing I don't like is their software's email alerting doesn't play nice with Exchange and I had to write shim code in PowerShell to do the emailing. Eaton now owns the PowerWare brand so they will be oriented more to server, datacenter and big iron than the little workstation models (I like APC for those.)