I decided that I wanted an irobot. I'm sure it caught my eye because I like the Isaac Assimov Foundation series. But also I like the idea of not having to try to vacuum under things and it still being clean. I've only had my roomba a few days. I'm not positive it gets every single speck of dust off the floor, but when I vacuum, I'm not certain I get every speck, either. In fact, I know I don't. The roomba happily crawls under the couch, tables, carts, etc.
When it finishes, and I don't know if it is finished or just needs to be recharged, I can use the swiffer to spot clean smudges. Then the floor looks good to me and I feel pretty pleased with the whole idea of a clean floor. It dragged dust bunnies around, and rolled some of them up and left them in the middle of the floor. It was easy to pick it up (since it wasn't under the couch). It's dark under there so if I lean over and poke the vacuum nozzle haphazardly around, it doesn't get all of it. So, the little dust bin was pretty stuffed with dust and dust bunnies, and more was rolled around and left for me to pick up.
I think maybe as I do it more, it will get cleaner and cleaner. I still had to vacuum in places the roomba couldn't wedge itself in to, but that still meant I wasn't doing as much.
I realize that I'm retired and have plenty of time to clean. I don't like cleaning any better now that I'm retired than I did when I was really busy all the time. But I still like it to be clean...and not just because I'm allergic to dust!