It's definitely not a total replacement for a hoover but they are great.
They need about 4 hours charge then run for about 3 hours.
You need to keep your floors clear of small toys, cables, bobbles etc and if you have lots of rugs, chairs/ stools with bars across the bottom (touching the floors) then it'll struggle. Similarly, if you have lots of furniture close together it may struggle to navigate them. It's best for open spaces and no/very, very minimal floor height differences.
Works better on hard floors than carpet. Great for under beds and sofas if your sofa is high enough. Won't fall down stairs but may strand itself on what it perceives to be a cliff edge (top of stairs, a sunny patch on the floor!).
Initially we emptied it twice daily but if you use it everyday then the amount to be collected is much less and we only empty once or twice a week.
One big bonus is there's just less dust in the house in general so less dusting of surfaces to be done.
I wouldn't want it running in the same room as me, noise-wise and if I haven't put the bar stools up on the island I don't run it overnight as it gets stuck and the error noise is loud enough to wake me up.
We replaced ours when the first one died. I'd replace it again.