i've seen the robomow, but i ended up buying a LawnBott, the red Evolution model. Having it over a year now, we just call it 'Evo' for short.
And for me and my yard, it does a great job. It does replace my having to cut the yard. I haven't mowed my own for a year, just let Evo handle it.
If your yard is right, i highly recommend the Lawnbott
