Setup was pretty easy, just make sure you're connected to a 2.4ghz wifi network.
The device itself looks decent, and fits in well with most home furnishings. Honestly, you probably won't notice it too much until you look for it, which is good - it's non-obtrusive.
I live in a pretty clean air city, and the sensor seems to indicate this quite accurately. Would be curious how it works in somewhere like Beijing or Shanghai. It's a well-designed device that does exactly what it advertises.