I have owned multigenerations of Roomba vacuums. The technology has progressed but there are still limitations to what can be done. I read a lot of comment that Roomba gets stuck in the same spot every time. This is an operator error. If you know it gets stuck in the same place, find a way to not make it get stuck. I added furniture pads under my bedposts to raise my bed .25 inches. Now Roomba cleans under my bed. We have a metal rack in one room that Roomba cannot climb over. I put hot water pipe insulation on the metal bar, problem solved. If you are going to own a robot, you need to understand the limitations.
I have never experienced a bin full error. I empty the bin at least once a week. The people complaining of this may need to rinse the bin under water. Yes, it is designed to be rinsed under water.
The mapping function seems to be more of a gadget than useful. There is no way to instruct the robot to clean only certain areas. Maybe this is possible in more expensive models. I will never know.
The cleaning pattern is random. Don't expect it to clean every inch of floor each time it runs. I schedule mine to run 3 times each week. It is enough to maintain the carpet between serious vacuuming and shampooing.
I am always impressed with the amount of debris this mighty little robot picks up. I prefer the new counter-rotating brushes to the old-style bristle brushes. I feel they pick up more stuff and do less damage to the carpet fibers.
The battery technology has vastly improved. I seldom got a year out of a battery in the older models. I have had the e1 for almost two years and the battery is as strong as the day I got it.
You can get replacement brushes on Amazon inexpensively. I have found them to be almost as good in quality as OEM brushes. They still perform well.
I highly recommend buying the protection program from SquareTrade. Any electronic device is going to have a short lifespan when used as often as a vacuum. You will be glad you bought it.
I have called iRobot on occasion, and they have always been quick to respond and very helpful.
Overall, I think iRobot has created a great product coupled with great support.