We've had several APC Smart UPS'es fail catastrophically and without warning. In one case, a 2200VA unit literally caught on fire!
I've seen 15-20 year old SmartUPS's catch on fire (always the front circuit board). The ones that don't flame up still have heat burn marks on the front circuit board. Must be a design flaw.
The SmartUPS 1500's from 10 years ago until now (once they started being black) are working 100% OK for me at 10 client sites (including my own). Never a failure. Just make sure you replace the batteries as soon as it tells you or it starts failing in weird ways. It's still my UPS of choice.
I'll check out the other brands you guys mention. Eaton is a well known company. Like you said though, it's not until 2-5 years later that you learn your UPS is crap.