I had one, which was brilliant once it had a wire buried round the edge of the grass and connected to power, which sent a radio signal to it when it was about to plough into a flowerbed This all took a bit of doing.
It worked well for about a year, wandering round the grass cutting as it went, and veering off at an angle when it detected the radio signal. I could program it to run the days I wanted, at a suitable time.
Then some animal visitors (I think foxes, but it may have just been a vole or a shrew) discovered the buried wire, dug it up at several places and chewed through it. I bought connectors, repaired the gaps by joining in lengths of wire, and reburied it. Quite soon after, the wire was dug up in other places. I did more repairs.
Then it just stopped working. I suspected I may have missed a gap, so I bought more wire and replaced the whole lot - finding a buried fault when all you know is that it is somewhere on the edge of a large lawn would have meant digging it all up anyway.
It never worked properly after that. It would start up fine, travel a couple of yards, then turn at right angles, travel two feet and stop dead. I've no idea what was wrong with it, and I couldn't find a dealer who would look at it and mend it. I gave it awat to someone who thought a friend of his could fix it. I don't know whether he succeeded.
