6% cheaper ≈ US$170
- Suction power 4,000 Pa vs 3,000 Pa
- Dustbin (robot) 400 ml vs 250 ml
- Dust bag (dock) 4 l vs 2.5 l
- Noise level 70 dB vs 68 dB
10 robot vacuum and mop combos at a similar price that compete with the X21 SW — what each does better, what it gives up and how the price compares.