Curiously, the Alen A375 name seems not logical. The Alen A350 covers up to 750 square feet and products usually increase the spec as the product number increases. Yet, the A375 only covers up to 650 square feet. That’s backwards from the usual situation.
I couldn’t say whether the Alen A350 is the best air purifier on the market for the money. It’s always practically impossible to single out one product as the best value. But if there were such an award, it would be in the running.