I'm a bit of a gadget geek, but my Roomba is perfect for me. It is set to run whenever there is no one in the house and it returns to its base on its own. I love that I can set it to clean while I'm at work and the kids are in school. No need to pay a cleaning service. I only have to empty the dirt bin on a regular basis.
I have a iRobot Roomba also. I dont remember the model, but it is the one that has extra cleaning feature after pets. Sometimes it can clean my flat for an hour and still continues to clean. But some times it spends less time cleaning, make a beep sound meaning it has finished, while there are still hair and dirt in corners. Sometimes he get under the table and cant get out from it for half an hour... I have taken it to the service and they said it works fine; average cleaning time is about 30-35min for a 70m2 flat. I could only say that iRobot is a great addition to a basic vacuum cleaner, as iRobot still misses some dirt.