Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Attractive, yes. Effective?

Attractive, quiet unit. I have it running in my finished basement. Appears to be well constructed. Several layers of filters. It's interesting to watch the unit ramp up when I smoke around it; it apparently detects the cigarette smoke and increases filtering. How effective the unit is only time will tell. I guess I'll see what collects on the filters and decide. So far it appears to be doing something, at least.