Continuous - always powered from batteries, which are charged when power is available. This handles not only power spikes or flat out outages (like standby models), but low power conditions as well as 0 cutover time (as there isn't a cutover).
He informed me all the Smart-UPS and the RS models in the Back-UPS line all offer continuous.
I'm posting this info for a few reasons:
1) So you don't have to call APC :)
2) What other series from other manufacturers offer continuous ups?
3) Debate the whole necessity of continuous vs standy
More info about my setup/goals if you're curious:
My whole plan is get my home machines (2), 1TB San (750 due to raid5 - old, eh?), Router/WIFI AP and cable modem hooked up to either 1 or 2 of these + an LCD at each desk. I'm divided whether I should get a higher rated unit for all, or 2 and split the load.
My main issue is power 'lows' - I've toasted 2 high end PSUs (along with mobo and vid card once), and the one I have now is working, but I suspect is not consistantly passing enough power to a hard drive that now refuses to stay on while under heavy use. I don't know if either are now 'damaged', but I'm fairly certain the source problem is power. I have a standby unit connected to my wife's computer currently, and occasionally it'll start beeping - leading me to believe stable power is an actual problem.
I plan on stopping by Home Depot on my way home for a Kill-A-Watt device so I'll know exactly what power rating I need.