I was given a used Roomba from my mother. My mother is disabled and bought a Roomba to help her clean her floors. It worked great on her laminated and carpet until she refloored her house with a darker colored carpet. The Roomba stubbornly refused to go on her new dark colored carpet. So she gave it to me to try and use it at my house. I'm not exactly sure what model it is, but my mother said she bought the most expensive, feature loaded one available.
Its a nice product, but from my experience it clearly has limitations.
Most days, it works fine. But other days, there are problems.
First off, my home has no carpet. Its only tile and laminate, some of it dark colored. The Roomba I was given is extremely tempermental--it would refuse to work on my mother's dark carpet, but would work fine on my equally dark tile and laminate flooring.
I think its ok for daily maintainence cleaning, but is no substitute for deep cleaning. I use it on the first floor of my house to pick up dust and pet hair throughout the week, and one day a week I still have to use a traditional vacuum or broom because it misses corners and won't clean under some furniture, and sometimes it gets mysteriously stuck under furniture or can't find its recharging station.
If I use it on the second story of my house, it would go near edge of the stairs, freak out, and turn itself off. (Defeating the purpose of a Roomba...I want a device to vacuum my house unattended while I'm not home!) Twice it actually fell down the stairs, even though my model has extra sensors in it that are supposed to prevent that sort of thing from happening!
If you have longhaired pets, the hair will get caught in the wheels, motor, blades, etc, and jam it up. I had to take mine apart every couple of weeks to clean it because our long haired cat's shed hair kept causing it to malfunction. (Now that I no longer have a long haired cat I don't have this problem anymore).
Also, if you have pets it may scare them, or run over them if your pets are lazy. One day I came home to a traumatized cat and a nonfunctioning Roomba because the machine had sucked up one my cat's favorite small toys. Oh yeah...if you have kids or pets who leave small toys lying around, they will get sucked up and jammed in the Roomba.
Also, it seems like my Roomba hates my husband. For some reason, EVERY time he turns it on, it malfunctions. Most days I use it, it works fine (within its limitations).
Noisewise, it is about half as loud as a traditional vacuum cleaner.
I've had my Roomba for about a year and I'm not sure if I would buy a new one, at least not without more updated, less stupid models being released.