Has anyone had experience with a robotic cleaner with an onboard battery that requires no cords or hoses at all?

When my pool was being designed in February, I ran across a website that offered these. You dropped it in and 4-6 hours later, you fished it out and stored it in a wheeled charging base. As I remember, the prices were in the $4,000.00 range.

I haven't been able to locate the website since, nor have I been able to establish whether they work effectively.

I don't like the look of leaving a corded cleaner in the pool. It definitely detracts from the overall appearance, particularly in a natural or lagoon pool.