I have used an Aquabot for nine years. It does a nice job of cleaning the entire pool. I throw it under the cover in the spring (I have a solid safety cover) and gets a nice head start. My only gripe is that it gets stuck on the ladder occassionaly. I have replaced every part (including the cord) over the years except for the handle, case and motor.

They can be found easily for $850 and the there are higher end models that have sensors that avoid the stairs and ladders.

Also, a simple trick to keep the robot from eating the cord is to wrap the cord with some old noodles that you would otherwise discard.