I'm solo in a small space (400-500 sq ft) with flat stained concrete and only half a dozen clients and delivery folks in and out of it every day. The Roomba is amazing.
Used to be anything hit the floor it'd have to go straight into the trash, now it's about as clean as you can get it at the start of every morning.
If you've got a really big place, or lots of wires and carpets and things that it can get hung up on it would be pretty frustrating. Since my place is so small and there's no rug, it'll go about 100 minutes every single day randomly cruising around cleaning.
I got one of the cheaper ones at ~$250, and it's done over 300, 100 minute jobs in less than a year, so we're getting down to pennies per hour. Only downside is you do need to empty it every day or two. I also have read that for smaller rooms the random ones will do a better overall cleaning job than the ones that map their surrounding and follow a grid.
Like 2B mentions, there are good industrial options out there for serious/bigger production environments.
