Dyson - Purifier Big+Quiet Formaldehyde vs Xiaomi - Mi Smart Air Purifier 4 Pro

The Purifier Big+Quiet Formaldehyde is the clear pick on raw spec strength, leading by 18.8 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.

Pick the Purifier Big+Quiet Formaldehyde if you care most about coverage / cadr. The biggest gaps in its favor are coverage, cadr, min noise.

The Mi Smart Air Purifier 4 Pro similarly does not carry a headline advantage on the popular specs — look at the full table for category-specific deltas.

Both ship with comparable true hepa h13+, activated carbon, so those specs do not separate the two — focus on the differences below.

Bottom line: the Purifier Big+Quiet Formaldehyde is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.