Anyone used the air purifier AS65? Need some advice based on practical experience on the device usage as well as service quality from LG PuriCare.

Some questions:
1. Why is the device and its replacement filters more expensive than "premium" brands out there e.g. Dyson? Both also HEPA and activated carbon and similar features, not sure what is the price difference for.
2. Under rental arrangement, the replacement filters are FOC but is the delivery of replacement filters FOC?
3. How noisy is the device at max settings?
4. Does it remove formaldehyde? Some salesman told me yes but all the materials I read so far says no, unless my info is from outdated versions.