Updated

High prices, missed areas, and a tendency to close doors behind them have given robotic vacuums a reputation for being novelties more than necessities. Our tests of three new robotic vacuums show that robovacs are getting better, though one is clearly the best of this trio.

iRobot Roomba 760
The $450 iRobot Roomba 760 is the only model that picked up every piece of paper, all the cereal and sand, and virtually all the rice we laid down on our test carpet. It also found its way out of tight spots and around extension cords. And like the others, you can program it not to run when guests or children are around. A random pattern with more passes over the same spot helped account for its cleaning, though that also meant the Roomba roved around our 12x16-foot test area four to five times longer than the other two before it returned to its charging base.

LG Hom-Bot Square LRV790R
The LG proved to be the quietest and, at $800, the most expensive by far. Instead of cleaning in a random pattern like the Roomba, the LG Hom-Bot Square LRV790R goes back and forth and typically covers a spot just once. A “turbo” mode kicks in on carpets, while a spot-cleaning mode lets the LG circle over a 4- or 5-foot area for several minutes. But it cleaned less thoroughly than the Roomba, picking up most of the rice and sand but simply pushing around some of the cereal. It couldn’t pick up the paper we dropped on bare floors. And it had trouble sidestepping power cords and narrow objects.

Neato XV-21
Contrary to its name, the $400 Neato XV-21 left the most litter behind while making the most noise. Its straight-line pattern picked up all the cereal from bare floors—and most of it from our carpet—and got most of the rice and sand. But the Neato couldn’t pick up paper. It also tended to trap itself between chair legs and could end up stopping short of its charging base as it ran down.

The bottom line. No robotic vacuum can match the deep cleaning you’ll get with the best upright and canister vacuums. We also suggest thinking twice about any robotic vacuum if you have shag carpeting or area rugs. Otherwise, consider the iRobot Roomba 760 for its less-lavish price. And consider it only for maintenance between primary vacuuming, not as an alternative to an upright or canister.

Uncertain about the right model for you? Check out our buying guide for vacuum cleaners before checking our vacuum Ratings, which show the best-performing models.

—Ed Perratore

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Copyright © 2005-2013 Consumers Union of U.S., Inc. No reproduction, in whole or in part, without written permission. Consumer Reports has no relationship with any advertisers on this site.