Lanx
<Prior Amod>
this guy has a good comparison w/ the worx and the husqvarna (1year ago i believe the husqvarna was the one to beat)The iRobot one looks awesome because it doesn't require any kind of wire or anything. The yard I'd want to put it in is a big rectangle with 3 sides going right up to the fence. The house side had some decorative...uh.....flourishes, but pretty damn simple overall.
I don't mind mowing at all, but fresh cut grass every other day sounds pretty awesome if it works even half as good as the vacuums.
take aways of the worx are the oversized wheels, it's off center cutting blades (so it can cut to the edge), and really high depth adjustment