Never bought one before, so don't really understand 200cfm.
But thanks for this pointer, Will look out for it in specifications.
This one from Xiaomi. Cheap, But dunno if good enough.
https://www.mi.com/sg/product/xiaomi-smart-air-purifier-4-lite/
The higher the cfm/cadr, the faster and efficient to clean the air.
Usually most brand will tell you the cfm and cadr. But the real world test determines how closed of what they disclosed.
Look for those air purifier that people tested online.
The others things is the noise Db. But I think is secondary unless you put in bedroom.
Filters for some brands got all the hepa thing. To me, good to have not a must.
Because of how good the cfm/cadr, my xiao mi gen 1 is still my go to air purifier for whole house. Suppliment with a smaller air purifier for bedrooms. Tested by people when China air quality was super bad. Hearsay gen 2 onwards are weaker and smaller but I didn't research into them.