Things are going well with Herman. He successfully keeps the grass cut and I have had few problems with him compared to a traditional riding lawnmower. I haven't seen any noticeable increase on my electric bill (but I'm not paying strict attention to it).
So far, here are the problems I have had:
Bad Motor - KA Robotics customer support sent me a replacement motor immediately and I had no problems replacing it without a screwdriver and an allen wrench. KA even sent someone to the house to pick up the old parts.
Getting Stuck - This was a substantial portion of the problems in the first month of robot slave ownership. I wasn't sure what constituted a trap for Herman, but I learned what quickly what caused him the most problems: ants and tree bases. The latter is easy to fix: flatten the base of the tree or wire around them. The ant hills are a bit trickier. The soil around my house is more appropriately described as a beach with grass on top. There is no top soil here, just sand. That means that when the ants make a mound, it's really just an unimaginative sand castle. As Herman runs over the hill day after day, the tunnels collapse and eventually form a sandy hole that no mortal Lawnbott can escape. The only solution is death for the ants. All of them.
Un-sticking Herman has gone from a once a day or more thing to a once every couple days. Over time, this too will decline as I hone my robot Feng Shui...
Paranoia - A Lawnbott is like a really expensive 22lb R/C car. It has a handle, making it easy for me to pick up, or easy for a thief to chuck in the bed of his truck. I've put him on my home owner's insurance specifically for this reason. I want his theft covered.
Path of Destruction effect - Herman is a machine. Pure and simple. He has a job to do and does not stop for things that are ... not grass. That includes: stray trash, the perimeter wire, rugs, etc. Unless the object is over 4 inches tall, it's getting beaten with a 3200 rpm metal plate. The kids in my house will grow up knowing that anything left in the yard is as good as gone.
Now that I've told you the bad, here is the good:
No Human Labor - I don't have to take time out of my weekend (read: free time) and battle the weather or Empirial X-gnats for the right to keep my lawn from becoming a jungle. Yeah, I still have to work in the yard, but weeding and landscaping is cake compared to the monotony of mowing.
No Gas - I don't have to be reminded of how expensive gas is every week just so I can keep my lawn pretty. I also get a small kick out of knowing that I am not polluting as bad as a gas mower. My electricity may come from nuclear, but that energy is still more efficient than internal combustion (I hope).
Cool Factor - I am the only person in town that even knew this kind of thing exists. When the neighbors ask about it, they assume that the robot nature of the appliance makes it magically out of their ability to comprehend or harness. I am the pioneer of the robot slave world. I have the secrets to make the automaton's obey. Skynet, ho!