It sounds like a good idea having an automatic vacuum cleaner clean the house while You are away. The advertisement says it will do its job, return to the base and recharge to be ready to be used for the next cleaning.
But does it actually work ?
Beware of cables, ropes etc. The robot can easily get tangled. It is inevitable. So, remove all cables from the floor, if You don\t want to find Your robot with strings around the brushes.
Battery life – will it be enough to clean the house ? It rarely is. And with time the battery performance degrades.
Stairs, steps, doorsteps – robot cleaners can not overcome them, so You have move them manually to the next room, over the doorstep. Stairs are not a problem, as far as current models have sensors and will not fall of the stairs, but still, You have to carry them to the next floor.
Container size is generally small and You will have to clean it manually after each cleaning session. You will have to clean the brushes as well and remove hairs and anything entangled.
So, budget or mainstream brand model ? I would go for the cheapest chines robot . Even the bog brand have too many problems and some unnecessary features, such as weekly cleaning programs and smartphone connectivity, which is useless if You don’t clean them manually or if the robot gets caught in a rope.