Wow, it sounds like you've had a rough go with your iRobot Roomba vacuum cleaner. But don't worry, not all users will have the same experience - sometimes things just don't work out, even with the best products.
From what I can gather, some users have reported similar issues with dust clogging internal sensors, but it's definitely not a widespread problem. In fact, a lot of Roomba users sing its praises and say it's been a reliable and efficient cleaning companion.
So, if you're feeling frustrated, my suggestion would be to reach out to iRobot's customer support for some expert help. They may have some tips for maintaining the sensors or troubleshooting any problems. In the meantime, try cleaning the sensors more often to keep your Roomba running smoothly.
And despite the inconvenience, it sounds like you still find the Roomba vacuum to be incredibly useful and effective. So hang in there!