Totally worth it. I don't remember how long they last. Might be
   15 minutes. Might be an hour. It's just a sealed lawnmower
   battery in a box with an inverter basically but they're cheap
   enough (and always going on sale). I think they also help with
   brownouts. During rainy season we get a LOT of brownouts. Power
   outs are less than they used to be, but we still get them a lot.
   All the freakin' naples lightning during rainy season. First few
   storms scare the crap out of me. Actually, I have GREAT RESPECT
   let's say for all lighning storms. I'll stay outside on the
   porch until the last second at my computer... but when there's a
   "flash-boom", I rush inside and scoop up my laptop with me.
   smile emoticon