I used the Bissell Spinwave mopper. It was easy to set up and use, and clean afterwards. But it couldn't get some of the ground-in marks off the floor, such as a couple of peas that had been trodden on. I had to scrub it with my socked foot. When I emptied the dirty water, it clearly had found quite a lot of dirt.
Trundling that mopper up and down left me with a backache.
So I've ordered a robot mop. Because it would be nice to only use the Bissell mopper occasionally. I've bought the ILIFE W400, normally £299, I found it for £226 on eBay. It has two tanks, one for clean water and one for dirty, and it works methodically, up and down and up and down. It doesn't have a "return to base" capability, but neither does the Bissell. So, I'll charge it up, fill it with water, and put it down to clean the floor. When it's done, I pick it up, take out the water tanks, give it a clean and put is back on charge.
The difference between this and the other two robots (Vicky the Proscenic and Bridget the Bagotte) is that although they have a mopping option, that option really isn't much use, whereas the ILIFE is designed for mopping.