I bought the 211+ on looks. I will admit that up front. It was the only purifier in the showroom that did not announce itself as an appliance — the gray fabric sock around the base reads as a piece of mid-century furniture, and you can swap it for blue or yellow if you want it to read as a different piece of mid-century furniture. After three months in my living room I still walk past it without registering it as a machine, which is more than I can say for most things with a fan inside.
The performance backs up the styling more than I expected. On speed two — quiet enough to watch TV next to without raising the volume — it cleared the room of cooking smoke in under half an hour. On full blast it is loud, in the way every purifier is loud at full blast, but I have rarely needed full blast. One-button operation, no app, no settings: you press the button, it cycles through three speeds, and a light tells you which one you're on. There is something restful about owning an appliance that has decided not to bother you.
Then there's the ionizer. The 211+ uses what Blueair calls HEPASilent, which is HEPA filtration plus a constant ionizing field that pre-charges particles so the filter grabs them more efficiently. The catch — and it is a real one — is that you cannot turn the ionizer off. Independent testing has shown that with the ionizer disabled, the cleaning time roughly doubles. The performance you are buying depends on the ionizer running, and ionizers produce trace ozone as a byproduct. The amounts are small and within California's limits, but "some" is more than "none." If that bothers you, this is not your purifier.
It also has no app, no timer, no child lock, no air-quality readout, and no scheduling. The single button is the entire interface. Most days I find that refreshing. The day I wanted to set it to ramp up during dinner prep and ramp down at bedtime, I found it limiting.
The two practical annoyances I'd flag from living with it: it is bulky and there are no handles or wheels, so moving it room-to-room is a hug-and-shuffle. And the top section detaches from the base if you grab it wrong, which I learned by lifting it the wrong way and watching the fan housing pop off in my hands. Nothing broke, but my heart stopped.
Filters run about seventy dollars every six months, which is higher than the category average. That is the recurring tax for owning this thing — figure on a hundred and forty a year on top of the $320 sticker, and Blueair has replaced the 211+ with the Max 211i if you want the current version with smart features bolted on.
Verdict: Buy this if you want a purifier that looks good and you don't mind an ionizer running all the time. If the ionizer is a dealbreaker, get the IQAir HealthPro Plus and pay more for the privilege.