Dyson has recently released a teaser video of thier robotic vacuum cleaner that suggests a September 4 release, or announcement as the only information on the video is '16 years. 200 engineers. £28 million investment'.
I think this will be 100% better than the roomba as from the video it looks like it will use path planning to intelligently vacuum your room rather than just aimlessly bumping around. It would also be cool if they can get it to return back to recharge and somehow emply itself too. Also I hope that this will not be crazy expensive!