We've recently bought one of these - and it's bloody brilliant.
We have a dog, so vacuuming needs to be done every day and was a real chore with both of us working ft (and dc not throwing themselves in to help).
The only thing it won't do is stairs, for obvious reasons.
It's buzzing around now, while I'm wasting time on MN - although am about to clear the floor in dc2's bedroom and send it around there.
On the advice of someone else here, have bought the extended warranty for 48 months as apparently there's a lot to go wrong with them.