What's the best backup sump pump?

If you're in the Chicago area, Trusty Warns (http://trustywarns.com) makes the best backup sump pump system. They are not cheap (mine was about $2K), but if you want peace of mind, they can't be beat. I live next to a creek and we've had 3 "100 year" floods in the past 20 years and never had it fail. Their system includes a 12v pump, batteries, charger, separate float switch, and outlet pipe so there's no single point of failure. (And every one of those pieces on the main system has had a problem over the years, including mice clogging the outlet.)