The battery-operated iRobot Looj 155 uses a rotating auger (rubber paddles and brush) to clean debris from gutters. You climb a ladder to place the device, then use a remote control in its removable handle to send the Looj back and forth and switch the direction of its auger's spin. Moving on rubber treads, the Looj "blasts through debris, clogs and sludge and brushes gutters clean." You can clean a 60-foot section in "10 minutes." The remote works from "up to 75 feet" away. We paid $170 for the Looj at store.irobot.com.
We loaded a 60-foot section of K-style 5-inch gutter with dry and wet oak leaves, inserted the Looj, and ordered it to get to work. We also tested the Looj at a staffer's house.
This robot is not so hot. It flipped many leaves back into the gutter or toward the roof instead of the yard. We dislodged dense leaves or debris only by working the Looj back and forth repeatedly. And the Looj sometimes became stuck and had to be retrieved mid-job.
Cleaning can be s-l-o-w. Although the device took 15 minutes to remove dry leaves from 60 feet of gutter, it took almost an hour to clear heavy spring debris from 50 feet at a staffer's home. (He usually does that job in 10 to 15 minutes.) The remote control's range varied from about 10 feet to 50. It did best when held in contact with an aluminum gutter. If you can't reach large stretches of your gutters, the Looj might make sense, but other cleaning methods are apt to be more effective.