Verro(TM) from IRobot Corporation, which is similar to the Kreepy Krauly(TM) and Aquabot(TM) pool cleaners, is a device you drop in your pool and simply let it clean the debris out of your pool. They will clean the pool bottom, stairs, and even the walls. IRobot's version of this comes in two different models which are designed very differently.
The Verro 300, the lower end model, has 4 wheels, a power supply, a filter bag, and an advanced pump to move the Verro as well as clean and suck in debris. Verro can clean your entire pool in 60-90 minutes from the floor to the water line. One of the benefits of verro is that as it cleans it distributes your pool chemicals around the water and maintains the pool temperature. Verro 300's filter bag can clean particles as small as 2 microns!!! Verro 300 is to be used in gunite pools and can guarantee your family will have a clean healthy pool.
Like the Verro 300, the 600 will circulate pool water and chemicals while it is cleaning. Unlike the 300, the Verro 600 can be used on all pool types - including fiberglass and vinyl - and can completly clean a pool in an hour. Design-wise the 300 uses four wheels and jets to move around and clean where the 600 uses squeegee brushes that gently scrub algae and dirt off of the bottum of your pool, larger debris is then sucked up into a filter bag similarly to the 300.
If you are looking into a robotic pool cleaner, Verro is the way to go!