I have quite a complex floor plan, and the Roomba 980 is the first robot which has no issues. The camera helps. I like reports showing where it cleaned. As opposed to the 8 series or lower, it cleans not in the random pattern, but vacuum clean as you would do the job (in rows). I highly recommend paying a bit more for the 980.
Have been using the Roomba for about 2 months now & apart from getting stuck occasionally under our couch or collecting a shoelace or similar, It has been performing fantastically. It has taken a little to get into a routine to remember to empty the onboard bin. I have noticed with regular vacuuming the dust levels on horizontal furniture is much much less.
Having bought the Dyson V10, I thought the menial task of vacuuming would become fun and cool... but nope. I still hated vacuuming. Whilst the Dyson is powerful, and has all the attachments and different bits, its clunky and difficult to store - especially in a one bedroom apartment. You always have to find the time to add on the attachments, whisk it around, charge it up, and start again. It's a daily annoyance, and in truth, I hate it. The Roomba fixes all these problems. Firstly, its a bloody great vacuum cleaner. Secondly, because its robotic, its goes about its business into all the nooks and crannies you avoid when you're vacuuming yourself (only the places you walk/can see). It's not that loud, either; but I set it to vacuum every single day on an automatic timer. When its finished, its parks itself back on its base station so that its always charged - genius! If for some reason I want to do a spot clean outside of the schedule, I can set it to clean either from my phone (when I'm away from the house, even the other side of the world!) or by pressing the button on top. 5/5 stars for me - the best gadget I've ever bought and well worth the money.