Just saw this on Amazon, cheaper than the previous sale ($489 in December).
I've already got one of these; they're super quiet and come with lots replacement first-layer filters, which is nice. Only drawback is that they're a bit bigger than other filters, so you need to find space for them.
I have a Winix Zero 4-Stage. If I don't have one already, I would get it. They are also good for removing cooking smell, smoke.
One thing I really like is washable pre-filter that is very satisfying to vacuum it.
However, for consumer grade air filter, do not expect Smart-Sensor to be accurate, they are just gimmicky.