Is anyone using these? How many would I need to keep my trading alive in the case of poer outage assuming I have to power the computer and the DSL (or cable) thing? Two or only one? I have no idea about it, never used them. The power outages do not happen that often, perhaps once or twice a year where I live, so I am just wondering if it makes sense to use these. Any opinions? BTW, what are the best prices for such devices? TIA.