As for the docking station, it's used to charge the navibot – a task that takes an hour or so. What makes the SR8855 particularly clever is it will return to the docking station when it's low on juice, charge up, and then return to where it left off. So if you live in a really large open plan house, you can leave it running while you're out safe in the knowledge that even if it takes all day, the whole house will be clean when you get home.
It's this idea of having the navibot run while you're out that really is key to its appeal. As such there's a timer for setting exactly when you'd like the cleaner to do its thing. Sadly it only has one setting, so you can't turn it off at the weekends (you can of course just turn the whole unit off instead).
If you'd rather take control yourself, the remote lets you do this by using the D-pad on the remote control to steer it around. Either using the remote or by pressing the buttons on top of the unit you can also set it to Max or Spot modes as well as the normal Auto mode. Max mode has the cleaner cover the same area twice while spot has it cover the square metre or so around where you place it on the ground – useful for little spills.
The unit we're looking at is the SR8855, which has touch buttons. An SR8845 is also available, but it has physical buttons and only includes one Smart Gate. It is otherwise identical, though.
The navibot itself is very well built with a thick rubberised strip round its edge protecting it, and whatever it bumps into, from harm. The shiny plastic used on the top isn't the most sensible choice due to its ability to highlight scratches and dust, but it's a minor point. Underneath, the two drive wheels are mounted on springs that give the wheels a good couple of inches of travel and allow the navibot to traverse quite sizeable changes in floor height. They also cope well with relatively rugged carpet, though long-weave shagpile-style carpets will foul it up. It can also have problems if it approaches a change in surface at an angle as the small balance wheel can catch on the edge and deflect the navibot.
Overall, though, the SR8855 is surprisingly accomplished at getting round a variety of rooms. With a press of the go button, it will start off straight away, zigzagging up and down until it meets an obstacle, at which point it will keep shimmying across until it can carry on. In my variously wooden, tiled and carpeted two-bedroom flat it cleaned the open plan kitchen and living room, my bedroom and en-suite, and the hallway within about an hour, which isn't half bad. In that time it didn't have to return to recharge once – it should last up to 90 minutes.