The Roomba works better than what I was even expecting, except for one pretty serious problem. The Roomba has sensors which "see" objects in front of it, so that way it will slow down before bumping in to them. This sensor works great for my walls, but it doesn't seem to see most of my furniture and bumps in to it at full speed. It seems like it doesn't see anything that's dark brown or black, which makes sense since it uses infrared to see. After the first time I let Roomba run free, I noticed a nick in the leg of my entertainment center. I also noticed a little wood splinter by my dresser that I can't figure out where it came from. Both of these were definitely from the Roomba, when it hits the furniture it's going fast enough to do some damage.
After reading a few web sites, I found a solution for this. Buy rubber sponge tape, and attach it all the way around the front bumper of the Roomba. That way, the rubber sponge will absorb the impact when the Roomba hits stuff at full speed. So far this has worked great! Here is a link to the roll of 1/4 inch thick, 3/4 inch wide, 10 foot long rubber tape that I bought from Hardware and Tools:
Make sure when you attach the rubber tape that you attach it at the bottom of the bumper, it shouldn't cover the sensors. As I learned the hard way, 3/8" is too thick, the Roomba won't be able to dock properly so be sure to get 1/4" thickness. Also the 3/4" width is just about right, any wider and it will cover the sensors.
The edges of the tape seem to start peeling off after lots of use. I think I'm going to try to put some two sided tape on the ends of the section that I cut off so it wont' peel off so easily.