Roborock Q10V vs Dreame D20: LiDAR navigation wins in cluttered homes

The [Roborock Q](https://www.amazon.com/s?k=Roborock+Q&tag=wehavethat-20)10V uses LiDAR and SLAM to map rooms and track its position, while the Dreame D20 relies on bump sensors and gyroscopic guesswork. In a home with furniture, toys, or tight corners, the LiDAR system actually cleans instead of wandering and missing spots. The bump-sensor approach works fine only in open, empty spaces.