We just got a Roomba 690 and have it used only once. We got a good price at Amazon. I really have a hard time vacuuming because of a bad back and I think I'm going to love it. It goes under the bed which is a big plus.
It goes over floors and carpet. I do think we will have to do(or have done) a vacuuming with the regular vacuum every few months to get into corners, etc. The noise isn't bad at all. It did take quite a while to complete the job but that's a minor issue I think we'll get used to.
My only problem right now is I'm having a problem setting up the phone app so I used it manually. No problem. I'm hoping to get the phone app working very soon.