We loooove Roomba! I haven't been able to lift for ages so DH got me one. We have floating floors and he's great. Probably not as good as I could do with the big vacuum, but good enough that the dust doesn't give me stress. Picks up all the kids leftovers too. He tells me when he's stuck/full/needs to be recharged.

I googled the cheaper models reviews and that was enough to stop me going with the cheaper ones. We got ours for under $400 in a Harvey Norman sale though (down from $600).