During walk about i managed to catch a glimpse of this lawn roomba doing its thing in the daylight, i have only really managed to see this little guy in the night with his little headlights on in the past. As you can see it does a fairly decent job of maintaining the yard for this place, but there are tufts of grass he tends to miss around the joint.
After looking into these items a little bit they seem to have gotten much 'smarter' in the past couple of years wnd those missed areas would not be an issue with a current model. that being said , decent units look to be in the 1500 to 3500 thousand dollar mark so its still pretty steep price wise for self maintaining lawn.
However, I assume that the technology will begin getting cheaper after the units hit max efficiency and the competition starts doing its thing... much like the vacuum robot wars.
link to some more info here