I love this feature! After a lifetime of throwing my socks on the floor, Roomba finally trained me to put them in the laundry hamper. I've learned to keep my floors tidy all the time, and my life is much better for it.
I like this feature, too! When I first got mine I had it set up to run only on certain days, as my small place doesn't need a lot of vacuuming. Then I discovered that the closer I got to the robot run, the tidier I was. So I wrote some code to make it run on random days, and that finally got me to stop trying to cheat.